US3556499A

US3556499A - Hardened steel members and method and apparatus for making the same

Info

Publication number: US3556499A
Application number: US355505A
Authority: US
Inventors: George L Hammon
Original assignee: Chemetron Corp
Current assignee: Chemetron Corp; Chemetron Railway Products Inc
Priority date: 1964-03-27
Filing date: 1964-03-27
Publication date: 1971-01-19
Anticipated expiration: 1988-01-19
Also published as: DE1458998A1; DE1458998B2; GB1086557A; CH449069A; DE1458998C3

Abstract

In apparatus for the hardening of a longitudinal surface of an elongate metal member, a heating means and a quenching means, means for advancing the metal member at a predetermined rate along a predetermined path and through the heating and quenching phases of said means, the heating assembly progressively heating a longitudinal surface portion of the metal member as it is advanced through the heating assembly to raise the longitudinal surface to or within the critical temperature range whereby the heated surface portion expands and causes a camber to be formed in the member, the quenching means progressively quenching the heated longitudinal surface portion of the metal member as the metal member is advanced, means including a pair of rollers one engageable with said longitudinal surface after said surface has been heated and quenched and the other engageable with the side of said elongate member opposite said surface and adjacent said heating assembly for applying opposite forces to the member while it is being heated to or within the critical temperature range in directions perpendicular to the camber so that the camber in the member is increased and the heated longitudinal surface expanded, and means for simultaneously moving the axis of each of said rollers toward the longitudinal axis of said elongate member.

Description

United States Patent George L. Hammon Oakland, Calif.

Mar. 27, 1964 Jan. 19, 1971 Chemetron Corporation Chicago, III.

a corporation of Delaware. by mesne assignments [72] Inventor [21] Appl. No. [22] Filed [45] Patented [73] Assignee [54] HARDENED STEEL MEMBERS AND METHOD AND APPARATUS FOR MAKING THE SAME 9 Claims, 23 Drawing Figs.

[52] US. Cl 266/4, 148/131, 158/274, 238/122 [51] lnt.Cl C21d 9/04, C21dl/l2,C21dl/62 [50] Field of Search 266/4, 2A, 5; 148/131, 152, 12.4; 238/122; 158/274; 155/99 [56] References Cited UNITED STATES PATENTS 2,542,940 2/1951 Pioch et al. 266/4 2,958,524 11/1960 Delapena et al. 266/4 2,570,883 10/1951 Stivin 148/131 2,969,299 1/1961 Fullerton et al. 148/131 1,987,841 1/1935 Rittershausen.... 148/39 3,117,041 1/1964 Koistinen 148/39 2,457,505 12/1948 Solem 158/99 2,5 80,502 l/1952 Anderson. 29/482X 2,882,191 4/1959 Swaal 148/152X 3,124,492 3/1964 Dewez 148/131X 3,266,956 8/1966 Bennewitz 148/131 FORElGN PATENTS 477,064 12/1937 Great Britain 266/2 1,931 4/1951 Japan 148/131 Primary ExaminerCharles N. Lovell Attorney-Flehr, Hohbach, Test, Albritton & Herbert ABSTRACT: 1. ln apparatus for the hardening of a longitudinal surface of an elongate metal member, a heating means and a quenching means, means for advancing the metal member at a predetermined rate along a predetermined path and through the heating and quenching phases of said means, the heating assembly progressively heating a longitudinal surface portion of the metal member as it is advanced through the heating assembly to raise the longitudinal surface to or within the critical temperature range whereby the heated surface portion expands and causes a camber to be formed in the member, the quenching means progressively quenching the heated longitudinal surface portion of the metal member as the metal member is advanced, means including a pair of rollers one engageable with said longitudinal surface after said surface has been heated and quenched and the other engageable with the side of said elongate member opposite said surface and adjacent said heating assembly for applying opposite forces to the member while it is being heated to or within the critical temperature range in directions perpendicular to the camber so that the camber in the member is increased and the heated longitudinal surface expanded, and means for simultaneously moving the axis of each of said rollers toward the longitudinal axis of said elongate member.

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INVENTOR. George L. Hammon Attorneys HARDENED STEEL MEMBERS AND METHOD AND APPARATUS FOR MAKING THE SAME This invention relates to hardened steel members and to the method and apparatus for making the same, and more particularly to hardened steel rails and the method and apparatus for providing hardened surfaces on steel members such as rails.

Over the years, considerable effort has been expended to develop a commercially feasible method and apparatus for the hardening of steel rails. Under certain of the methods heretofore developed and being utilized at the present time, flame or induction heating is utilized for heating the rail, after which the rail is quenched with water, compressed air or other medium to obtain the desired hardness. The primary difficulty with such methods is that the rail, after it has been treated in this manner, if deformed which makes it necessary to perform additional steps to straighten the rail. This generally is undesirable, time consuming and very costly. For these reasons and others, many efforts have been made to eliminate this difficulty. For example, many have attempted to preform or precamber the steel rails before hardening to offset the contraction which takes place during cooling after heating one side as, for example, heating the head of the rail sections. Precambering of the rails is expensive and time consuming because it requires expensive equipment and, in addition, greatly limits the speed at which the rails can be heat treated. In addition, even with such precambering, it has been difficult to obtain rails which are sufficiently straight after heat treating without additional straightening which introduces undesired stresses in the rail sections. Also, with conventional hardened rails, considerable difficulty has been encountered because of shelling, cracking and the like. In view of the foregoing, there is a need for a new and improved hardened steel member, and a new and improved method and apparatus for making the same.

In general, it is an object of the invention to provide a new and improved hardened steel member, and a method and apparatus for making the same which overcomes the above named disadvantages.

Another'object of the invention is to provide a hardened steel member which has hardened portions-or zones of substantially uniform depth extending inwardly from the surface of the member.

Another object of the invention is to provide a hardened steel member of the above character in which there is a gradual transition on the interface between the hardened portion or zone and the remaining unhardened portion of the member.

Another object of the inventionis to provide a hardened steel member of the above character which is stress relieved throughout its length after the heat treatment.

Another object of the invention is to provide a hardened steel member of the above character in which the hardness pattern of the hardened zone or portion in the member is substantially uniform in a plane substantially parallel to the plane of the longitudinal surface of the member which has been hardened.

Another object of the invention is to provide a hardened steel member of the above character in which the hardened zone or portion has very desirable uniform microstructure.

Another object of the invention is to provide a hardened steel member of the above character which has additional desirable physical properties as, for example, resistance to shelling.

Another object of the invention is to provide a hardened steel member of the above character which can be easily and economically produced.

Another object of the invention is to provide a method and apparatus for the making of hardened steel members in which it is possible to heat treat the steel members continuously.

Another object of the invention is to provide a method and apparatus of the above character in which the members do not require restraightening after they have been heat treated.

Another object of the invention is to provide a method and apparatus of the above character which can be utilized on new and used steel members as, for example, steel rails which have been put into use without substantial advance preparation.

Another object of the invention is to provide a method and apparatus of the above character in which substantially perfect straightness in both vertical and horizontal directions can be obtained without restraightening.

Another object of the invention is to provide a method and apparatus of the above character in which curves or cambers can be placed in the steel members in either vertical or horizontal directions.

Another object of the invention is to provide a method and apparatus of the above character in which pressure is applied to the steel member before it is completely quenched.

Another object of the invention is to provide a method and apparatus of the above character which can be used in the laying of continuous rail as, for example, in the laying of continuous rail by butt welding of new and relay rail by the Schlatter process.

Another object of the invention is to provide a method and apparatus of the above character in which the economics and flexibility achieved are particularly outstanding.

Another object of the invention is to provide an apparatus of the above character which is readily portable so that it can be readily moved from one side to another or can be mounted on wheels so that it can be used inthe continuous laying of hardened rail.

Additional objects and features of the invention will appear from the following description in which the preferred embodiment is set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

FIG. 1 is a top plan view of apparatus for making hardened steel members incorporating the present invention.

FIG. 2 is a front elevational view of the apparatus shown in FIG. 1.

FIG. 3 is an enlarged cross-sectional view taken along the line 3-3 of FIG. 2 showing a receiving rack for receiving steel members such as rail sections for hardening.

FIG. 4 is a cross-sectional view taken along the line 4-4 of FIG. 2 showing the drive mechanism for driving certain of the drive rollers of the supply conveyor assembly utilized in the apparatus.

FIG. 5 is a cross-sectional view in plan taken along the line 5-5 of FIG. 4.

FIG. 6 is an enlarged side elevational view looking along the line 6-6 of FIG. 1, and showingin particular the heating and quenching assembly forming a part of the apparatus.

FIG. 7 is a cross-sectional view taken along the line 7-7 of FIG. 6.

FIG. 8 is a cross-sectional view taken along the line 8-8 of FIG. 6.

FIG. 9 is a cross-sectional view taken along the line 9-9 of FIG. 6.

FIG. 10 is a cross-sectional view taken along the line 10-10 of FIG. 6.

FIG. 11 is a cross-sectional view taken along the line 11-11 of FIG. 6.

FIG. 12 is an enlarged side elevational view with certain portions broken away of the portion of the heating and quenching assembly shown in FIG. 6.

FIG. 13 is a cross-sectional view taken along the line 13-13 of FIG. 12.

FIG. 14 is a side elevational view in cross section of one of the burners utilized'in the top burner assembly of the heating and quenching assembly.

FIG. 15 is a view looking along the line 15-15 of FIG. 14.

FIG. 16 is a cross-sectional view taken along the line 16-16 of FIG. 14.

FIG. 17 is a side elevational view in cross section of one of the burners of the bottom burner assembly of the heating and quenching assembly.

FIG. 18 is a view looking along the line 18-18 of FIG. 17.

FIG. 19 is a cross-sectional view taken along the line 19-19 of FIG. 1 and particularly shows the shipping rack for the apparatus for storing the steel members after they have been heat treated.

FIGS. 20A and 20B are cross sections of hardened rails processed with the apparatus shown in FIGS. 119 with the present method under different rates of speed to provide hardened zones of three-eighths inch and one-half inch in depth respectively.

FIGS. 21A and 21B are macrographs of a longitudinal section and a cross section, respectively, of a hardened rail manufactured with the apparatus shown in FIGS. ll9 and showing the enveloping hardness pattern.

In general, the apparatus of the present invention for the hardening of a longitudinal surface of a metal member, particularly a steel member, consists of means for supplying heat to the surface to heat said surface to the critical heat, means for quenching said surface and means for applying a force to cause stretching of the longitudinal surface before it has been completely quenched so that when the steel member cools, it will be absolutely straight.

In particular, the apparatus of the present invention for the hardening of steel members is shown in FIGS. 1-19 and consists of a receiving rack 29 (see FIG. 1) which carries a supply of steel members, such as rail sections 31, to be hardened. The members 31 are supplied by a loading station to a supply conveyor assembly 32 which conveys the members to a heating and quenching assembly or apparatus 33. After the members have been heated and quenched, they are carried by a discharge conveyor assembly 34 to an unloading station 35, and eventually delivered to a shipping rack 36. A control panel 37 is provided for controlling the apparatus and controls the flow of oxygen from a liquid oxygen tank 38 through a converter 39. It also controls the fuel gas and the water used in the apparatus as hereinafter described.

As shown in FIG. 3, the receiving rack 29 consists of reinforced spaced parallel support structures 41 which each have' a downwardly and forwardly inclined upper surface 42 and which is faced with a suitable material such as a steel rail section 43. As can be seen from FIG. 1, three of the reinforced structures 41 are provided to form the rack 29.

The steel members 31 to be heat treated are unloaded onto the rack 29 so that they extend transversely across the rack. The lower end of the receiving rack 29 extends into the loading station 30. As shown in FIGS. 2 and 9, the loading station consists of a pair of support posts 48. A crossmember 49 is mounted upon the posts and carries a davit 51. A chain hoist 52 (see FIG. 2) is hooked into the davit 51 and is used for loading the steel members from the rack 29 onto the supply conveyor assembly 32.

The supply conveyor assembly 32 consists of a pair of spaced parallel longitudinally extending I-beams 53 disposed adjacent the lower end of the receiving rack 29. The I-beams are supported in a suitable manner such as by stands 55. A plurality of rollers 54 are mounted upon shafts 56 which are rotatably mounted in bearings 57 carried by the I-beams 53. As can be seen, particularly from FIG. 3, the rollers are positioned so that their upper surfaces extend slightly above the upper flanges of the I-bearns 53. The rollers are of substantial width so they are adapted to readily carry heavy steel members such as rail sections.

The first three rollers 54, counting from the left in FIG. 1, are free-running rollers, whereas the fourth roller, counting from the left, is a powered roller and is disposed adjacent the forward end of the receiving rack 29 so that it is adapted to advance a steel member loaded upon the roller 54 adjacent the receiving rack 29.

The fourth roller 54, from the left as viewed in FIG. 1, is driven from the fifth roller which is powered by suitable means such as shown in FIGS. 4 and 5 of the drawings. As shown therein, a gear motor 61 is provided on a base plate 62 positioned below the I-beams 53 and extending laterally of the I- beams. The gear motor 61 consists of an electric motor 63 which operates at a suitable speed such as 1750 rpm. which drives a speed reducer 64. The speed reducer 64 is connected to a clutch 66 by a coupling 67. The clutch 66 can be of any suitable type such as an air-operated or a hydraulicallyoperated slip clutch. The clutch drives a shaft 56 which is rotatably mounted in bearings 57 and upon which the fifth roller 54 is secured. A sprocket 69 is also fixed to the shaft 56 and drives a chain 71. The chain 71 driv'esa sprocket 72 (FIG. 5) mounted on a shaft 73 for driving'tlie roller 54 mounted thereon.

The conveyor assembly'32 includes means for guiding the steel members 31in a lateral direction as they 'are advanced and means for applying downward pressure to the steel members so that they will frictionally'engage the drive rollers 54 to ensure a positive advance. As can be seen in FIGS. 4 and 5, the means for guiding the steel members 31 laterally consists of side guide rollers 74 which are rotatably mounted upon studs 75 attached to the upper side of one of the I-beams 53. One of the side guide rollers 74 is provided adjacent each of the rollers 54 and is mounted in a fixed lateral position on the I-beam 53. The rollers 74 are positioned on one side of the path for the member 31 and serve as a lateral reference for guiding of the steel members 31.

Additional side guide rollers 76 are provided on the other side of the path for the steel members 46 and are mounted on the other I-beam 53. The side guide rollers are rotatably mounted upon studs 77 carried by brackets 78. The brackets 78 are pivotally mounted upon a bolt 79 affixed to the'l-beam 53. Means is provided for shifting each of the rollers 76 about its pivot between different lateral positions and consists of a side guiding fluid actuator 81. The fluid actuator consists of a cylinder 82 which is secured to the I-beam 53 and a reciprocable piston rod 83 which has its outer end secured to the bracket 78. I

From FIG. 5, it can be seen that as the piston rod is advanced, the side guide roller 76 is moved angularly toward the member 31 to urge the member 31 into engagement with the side guide rollers 74 as it is advanced. When the piston rod 83 is retracted, additional space is provided between the side guide rollers 76 and the side guide rollers 74 to permit members of a larger size to pass therebetween. From the foregoing description, it can be seen that it is the purpose of the side guide rollers 76 to continuously maintain the steel members being handled by the conveyor assembly 32 in the same lateral position by causing them to engage the side rollers 74 which have fixed lateral positions.

As pointed out above, means is also provided for continuously urging the steel members into engagement with the rollers 54 and, in particular, the driven rollers 54. This means consists of top guide rollers 86 positioned over certain of the driven rollers 54 so as to ensure that the driven rollers 54 positively and continuously advance the members 31. The top guide rollers 86 are rotatably mounted upon stud shafts 87, as shown particularly in FIG. 4. The stud shaft 87 is mounted in a bracket 88. The bracket 88 is pivotally mounted on'a pin 89 carried by a pair of upstanding members 91 affixed to the I- beams 53. Means is provided for moving the bracket upwardly and downwardly and consists of a holddown fluid actuator 92 which has a cylinder 93 affixed to the crossmember 94 carried by the members 91 and a piston rod 95 connected to the bracket 88.

Means is provided for controlling the application of fluid to the holddown actuator 92 and also to the side guiding actuators 81. Thus, as shown in FIG. 5, a control switch 96 is provided which has a follower 97 which senses the position of the associated bracket. As long as a steel member 31 is passing between the side guide rollers, the control switch 96 is actuated by the application of fluid to the cylinder 82 to thereby cause the application of pressure by the side guide rollers 76 to maintain the steel members 31 in engagement with the side guide rollers 74. Similarly, pressure is continuously applied by the top guide rollers 86 to urge the steel members downwardly into engagement with the driven rollers 54.

A protective housing 99 is mounted over the fifth roller 54, counting from the left-hand end as viewed in FIG. 1, and also serves to enclose the gear motor 61 and associated drive mechanism. The sixth roller, counting from the left-hand end as viewed in FIG. 1, is covered with a housing 101. Also covered by the housing 101 is an idling side guide roller 74. The seventh and eighth rollers 54 are covered with separate housings 102. The ninth roller, counting from the left-hand end, is covered with a housing 103.

Means is provided for driving the rollers 54 enclosed within the

housings

102 and 103 and, as shown in FIG. 7, consists ofa motor 106 mounted upon a base plate 105 secured to the I- bearns 53. The motor 106 is connected by an air operated slip clutch 107 to a speed reducer 108. The motor 106 can be operated at any suitable speed as, for example, 1750 rpm, and the speed reducer 108 can reduce the speed by a suitable ratio such as l200zl. The speed reducer 108 and the motor 106 are enclosed within a separate housing 109.

The output shaft of the gear motor drives a sprocket (not shown) which drives a chain 111. The chain 111 drives a sprocket 112 which is affixed to a shaft 113 which is rotatably mounted in the I-beams 53 by bearings 57. Additional sprockets 115 and 116 are affixed to the shaft 113 and drive chains 117 and 118, respectively (see FIG. 6). The chain 117 is looped over a pair of sprockets (not shown) which are affixed to the shafts (not shown) which drive the rollers 54 under the housings 102. Thus, it can be seen that a substantial number of the rollers 54 are powered or driven to thereby continuously advance the steel members 31.

The gear motor 61 and the motor 106 and associated speed reducer 108 are provided with means whereby the output shaft speed can be adjusted. Normally, the speed of these devices is adjusted so that the steel members which are being conveyed are conveyed at a slightly faster rate than they are received inthe heating and quenching assembly 33 so that each steel member 31 will be in contact with the steel member which is ahead of it to thereby, in effect, provide a steel member which appears to be continuous. Thus, as soon as a steel member is loaded onto the conveyor assembly 32, the fourth roller from the left, as viewed in FIG. 1, will engage the bottom of the steel member and advance it into engagement with the steel member which has just been advanced to very shortly thereafter cause it to engage the rear end of the steel member previously advanced and to maintain it in continuous contact with the previously advanced member.

The conveyor assembly 32 serves to advance the steel members 31 into the heating and quenching assembly 33. The heating and quenching assembly 33 includes means for heating and quenching a longitudinal surface of the steel member 31 (see FIG. 1). The heating and quenching assembly consists of a framework 121 comprised of four

vertical pipes

122, 123, 124i and 125 (see FIGS. 8 and which form a rectangular framework.

Pipes

122 and 123 are affixed to longitudinally connecting members 126 (see FIG. 9). One end of each of the members 126 rests upon the ends of I-beams 53 and the other end of each of the members 126 rests upon spaced parallel, longitudinally extending I-beams 127 forming a part of the conveyor assembly 34 (see FIGS. 6 and 13). The connecting members 126 have been provided in place of continuous I- beams to make it possible to separate the complete hardening apparatus into separate parts to facilitate transportation of the same to different locations. It is rather apparent that, if desired, continuous I-beams could be utilized for the entire apparatus. The

pipes

124 and 125 are affixed to the I-beams 127 by suitable means such as brackets 128 (see FIG. 10).

The heating and quenching assembly or apparatus 33 as shown in FIG. 12 also consists of a top heating assembly 131 and a quenching assembly 132 mounted within the framework 121. The top heating assembly 131 consists of a plurality of burners 133. As shown in FIG. 14, each of the burners consists of a burner head 134 and a burner supply pipe or mixed gas tube 136 which is connected to a cooling manifold 137. The manifold 137 is utilized for supplying a suitable cooling fluid such as water to the burner head. Each of the burners also includes a fuel supply pipe 138 which is connected to another manifold 139 which can be identified as a fuel and oxygen manifold 139. Each of the burners also includes a mixer assembly 141 mounted upon the manifold 139 and which is connected to the manifold 139 by

pigtails

142 and 143. The manifold 139 is supported upon the manifold 137 by suitable means such as tie rods 146 which extend. through both manifolds and spacers 147 mounted on the tie rods and positioned between the manifolds as shown particularly in FIG. 14.

In the embodiment shown, the quenching assembly 132 is constructed in a manner identical to the burner assembly 131 to make possible greater flexibility of use of the apparatus. Thus, each of the quenching devices is constructed in a manner identical to the burners 133 to make it possible for the quenching devices to also be utilized as burners or for certain of the burners to be utilized as quenching devices. The quenching devices can be simplified considerably if such versatility is not desired because normally, it is only necessary to supply one fluid medium, namely, air, as a quench for the steel member being heat treated.

Means is provided so that the heating and

quenching assemblies

131 and 132 ride upon and are guided by the steel member 31 being heat treated. As shown in FIG. 12, this means consists of a pair of semicircular hard faced shoes 151 engaging the longitudinal surface of the member to be heat treated. The shoes 151 are connected to opposite ends of the heating assembly 131 and the quenching assembly 132 by brackets 152. The heating assembly 131 and the quenching as sembly 132 are tied together by a connecting link 153 so that they are moved as a unit.

Means is provided for permitting vertical and lateral adjustment of the shoes 151 with respect to the brackets 152 and consists of two plates 154 and 156 which are dovetailed together to permit lateral movement of one with respect to the other. The bracket 152 is secured to the plate 154, whereas the plate 156 is secured to a bracket 157 which carries the shoe 151. The bracket 157 is provided with a slot to permit vertical adjustment of the bracket with respect to the plate 156. A side semicircular hard faced wear shoe 158 is also carried by each of the brackets 157. The wear shoes 151 and 158 engage a top longitudinal surface and a side longitudinal surface of the member being heat treated and serve to properly position the heating assembly and the quenching assembly as the members 31 are advanced therethrough.

Means is provided for mounting the heating assembly 131 and quenching assembly 132 to permit limited movement in a lateral direction and to permit vertical movement of the same. In addition, the same means serves as means to yieldably support a substantial portion of the weight of the heating assembly 131 and the quenching assembly 132. This means consists of a spring-loaded plunger 161 mounted within a cylinder 162 (see FIG. 10). The cylinder 162 is affixed to a crossmember 163 affixed to extension members 164 secured to the manifold 137 (see FIG. 12). At one end, the spring-loaded plunger 161 is pivotally mounted in a crossmember 166(FIG. 8) which is affixed to the

pipes

122 and 123. On the other end, a roller 168 is rotatably carried by the plunger and is adapted to travel upon a crossmember 169 affixed to the

pipes

124 and 125. From the arrangement shown in the drawings, it can be seen that any desired portion of the weight of the heating assembly 131 and the quenching assembly 132 can be carried by the spring-loaded plungers merely by changing the force which is exerted by the spring within the cylinders 162. It should be appreciated, however, that there should be sufficient weight applied to the top shoes 151 so that the top shoes 151 will always engage the top longitudinal surface of the member 31 being treated. However, the downward pressure should be insufficient to cause undue wear to the shoe or cause the shoe to deform or in any way damage the surface being treated.

Means is provided for continuously and yieldably urging the entire heating assembly 131 and quenching assembly 132 in a lateral direction so that the side wear shoes 158 are also always in engagement with a side longitudinal surface of the member 31. As shown in FIGS. 8 and of the drawings, such means can consist of weights 171 carried by steel cables 172 passing over pulleys 173 affixed to the framework 121 and secured to the brackets 152 by a hook 174. From the foregoing description, it can be seen that one end of the unitary heating assembly 131 and the quenching assembly 132 is pivotally mounted within the framework 121'so that the entire assembly can be pivoted about this one pivot point and that the other end can be shifted laterally of the framework 121 so that the heating assembly 131 and the quenching assembly 132 can follow and be guided by the longitudinal surfaces of the member 31 as it passes through the heating and quenching assembly 33. i

As hereinbefore explained, each of the burners 133 includes a mixer assembly 141. As shown in the top of FIG. 14, the mixer assembly consists of a mixer body 176. A mixing unit 177 is threaded into the mixer body 176 and is provided with a row of spaced circumferentially arranged ports 178 and another row of circumferentially arranged ports 179 parallel to the row 178. The ports 178 and 179 open into

annular chambers

181 and 182 respectively formed between the mixer body 176 and the mixing unit 177. The ports 178 and 179 communicate with a passage 185 provided in the mixer body which also communicates with the mixed gas tube 136.

Controlled amounts of gases are supplied to the

chambers

181 and 182 by manually

adjustable valves

183 and 184 provided in the mixer body 176. Each of the

valve assemblies

183 and 184 is provided with a valve member 186 operated by a control knob 187. The

valve assemblies

183 and 184 are adapted to control the flow of gases through passages 189 and 188 into the

annular chambers

181 and 182, respectively. A check valve assembly 191 is provided in each of the passages 188 and 189 and is mounted in a connector 192. The passage 188 is connected to the pigtail 142 which supplies the fuel' to the burner, whereas the'passage 189 is connected to the pigtail 143 which supplies the oxygen or other suitable gas to the burner. As shown in FIG. 14, the pigtail 143 is connected to the fuel gas and oxygen manifold 139 so that it communicates with the chamber 194. Similarly, the pigtail 142 communicates with the chamber 196 of the manifold 139. The chamber 194 is connected by a hose 197- to the oxygen pipe 124, and similarly the chamber 196 is connected by a hose 198 to the fuel gas pipe 125 (see FIG. 6).

From the foregoing, it can be seen that the fuel gas and oxygen enter the mixer and are thoroughly mixed in the mixer in controlled quantities and are supplied through ,the mixed gas tube 136. The tube 136 is threaded into a burner block- 201 (see FIG. 14) carried by the manifold 137 and feeds the mixed gases to a passage 202 provided in the block. A multisection tube 203 extends into the passage 202 and supplies the mixed gases to a passage 204 provided in a support member 206 which forms a part of the burner head 134. The burner head 134 also consists of a substantially rectangular boxlike framework 207 which is secured to the support member 206, as can be seen particularly from FIGS. 14 and 15. This boxlike framework consists of a pair of spaced parallel sidewalls 208 and spaced parallel end walls 209 which have their upper extremities secured to the support member 206. The boxlike framework 207 also includes a bottom member 211 which is secured to the lower portions of the side and end walls to provide a completely enclosed space in cooperation with the support member 206.

The bottom member 211 has a unique conformation so that the burner is particularly adapted to heat treat steel members of a particular conformation and in particular heads of steel rails as shown in the drawings. As shown particularly in FIG. 14, the bottom member is formed so as to provide a relatively wide U-shaped recess 212 through which the head of the rail can pass. Preferably, the bottom member is formed so that a predetermined uniform space is provided between the longitudinal surfaces of the rail head to be heat treated and thebottom. member to obtain the desired heat treatment as hereinafter described.

The enclosed space defined by the boxlike framework 207 mounted upon the support member 206 is divided into two separate chambers 213 and 214 by a divider plate 216 secured to the side and end

walls

208 and 209. Chamber 213 can be termed the mixed gas chamber because. it is in communication with the passage 204 provided in the support member 206. The chamber 214 can be called the water-cooling chamber because water is supplied to the chamber 214 through a pair of tubes 217 (see FIG. 16) mounted in the support member 206 and which extend through the plate 216. The two tubes 217 are connected by a laterally extending passage 218 provided in the'support member 206. A longitudinally extending passage 219 connects the passage 218 to a vertically extending passage 221 provided in the support member 206; The passage 221 is connected by tubing 222 to a passage 223 provided in the burner block 201 (see FIG. 14). The passage 223 communicates with a chamber 224 provided in the water manifold 137. The chamber 224 is connected to the pipe 123 by a hose 226 (see FIG. 8).

Water is removed from the chamber 214 through a tube 228. The tube 228.cxtends upwardly through the plate 216 and communicates with a passage 229 provided in the support member 206. The passage 229 communicates with a vertical passage 231 provided in the support member .206. The passage 231 opens into a reducer 232 and a tube 233. The tube 233-is mounted in the burner block 201 and opens into a cylindrical passage 234 which communicates with an upwardly extending passage 236. The passage 236 communicates with a chamber 238 provided in the water manifold. The chamber 238 is connected by a hose 239 to the pipe 122.

A large number of very small burner tubes 241 are provided for supplying the mixed gases to the large number of burner ports 242 provided in the bottom member 211 (see FlGS. 14 and 15). -As can be seen, the burner tubes are of various lengths and extend through the plate 216 and open into the mixed gas chamber 213 above the'plat'e 216. It will also be noted that the small burner tubes are spaced apart a substantial distance so that a cooling fluid such as water may readily flow between the same so as to keep the burner face which is formed by the bottom member 211 relatively cool during operation of the burner. Also, it should be noted that the burner ports 242 and the burner tubes 241 communicating with these ports are arranged so that the burning mixed gases jetting therefrom are jetting in directions which are perpendicular to the longitudinal surfaces of the rail being heated. Since it is desired to heat treat the longitudinal side surfaces of the rail head, it is necessary, as can be seen from the drawings, that certain of the burner tubes 241 be bent at substantially right angles.

As hereinafter explained, cooling fluid is supplied under substantial pressure to the burner head. Two inlets are:provided into the water cooling chamber 214 (seeFlG. 14) with only one outlet to ensure that there is always a greater inlet pressure than outlet pressure to thereby prevent cavitation within the chamber 14 and to thereby ensure that all portions of the outer face of the bottom member 211 will be properly cooled at all times during operation of the'burner.

As can be seen from FIG. 12, a plurality of the burners 133 are mounted side by side as, for example, eight burners as shown in the drawings to form the heating assembly 131 for heating the top longitudinal surfaces of the steel member to be heat treated. As hereinbefore explained, because of the fact that on certain occasions it may be desirable to use more than eight burners and to use a smaller number of quenching devices, the quenching devices have been constructed in an identical manner. The quenching devices are water cooled in the same manner and the water manifold 137 is supplied with water in the same manner. However, in place of gases such as oxygen and fuel gas supplied to the manifold 139 in the heating assembly 131, compressed air under relatively high pressure is supplied to the manifold 139 of the quenching assembly 132 so that quenching air is supplied'from the ports 242. The heads of the quenching devices are shaped in an identical manner so that the cooling air jetting therefrom will be delivered in small streams in directions which are perpendicu lar to the surfaces of the rail head engaged by the small streams of air.

As shown in FIG. 12, the heating and quenching assembly 33 also includes a bottom heating assembly 246 whichconsists of a plurality of burners 247. The burners 247 are mounted in a water manifold 248 which is connected to the

water pipes

122 and 123 in the same manner as the water manifold 137. The burners are also connected to a gas manifold 249 which is connected to the

pipes

124 and 125 in the same manner as the gas manifold 139. Pigtails 251 are provided for supplying the gases from the gas manifold 249 to the mixer assemblies 252 which areidentical to the mixer assemblies 141 hereinbefore described. The gas from the mixersis supplied through a tube 253, as shown in FIG. 17, to a passage 254 provided in a support member 256. A boxlike enclosure 257 having four sidewalls 258 is secured to the support member 256 and a top wall or bumer face 259 is provided to define an enclosed space. This space is divided into a gas chamber 26Iand a water chamber 262. by a plate 264. The burner face plate is provided with a large number of spaced burner ports 266. Burner tubes 267 extending into the gas chamber 262 and through the water chamber 261 supply mixed gases from the chamber 261 to the burner ports 266. Cooling-water is supplied to the chamber 261 by an inlet tube 268 and a tube 269 is provided for withdrawing water from the water chamber 261. The tube 269 communicates with a reducer 271 and the reducer is connected to an outer tube or water jacket 272 which is connectedto the water manifold 248 in the same manner in which the tube 233 communicates with the water manifold.

A suitable number of the burners 247 are provided as, for example, three burners as shown in FIG. 12 for providing bottom heat to the members to be heat treated for a purpose hereinafter described. 1

Means is provided for protecting certain parts of the heating and cooling apparatus from the very intense heat-which is generated by the burners 133. Thus; for example, there has been provided a pair of heat deflectors or heat shields 276 (see FIGS. 8 to 10). The heat shields 276 are formed by a metal backing member 277 faced with a sheet 278 of suitable heat insulating material such as asbestos which is secured to the metal member 277. The lower portions of the heat shields 276 rest upon the burner heads as shown particularly in FIGS. 8 and 10 and extend upwardly and outwardly therefrom and are secured to the pipes forming theframework 121 by suitable means such as straps (not shown). These heat shields serve to protect the upper portions of the burners and the manifolds which are utilized for supplying the burner.

Additional heat shielding meansis provided in the form of upwardly inclined water cooled shields 281 which are affixed to the framework 121 and which are faced with a suitable insulating medium such as flrebrick 282. It will be noted that the shields 281 also extend upwardly and outwardly and are positioned in such a manner that the firebricks 282 are disposed opposite the top heating assembly 131 so that the flames and the intense heat therefrom will be deflected upwardly and outwardly away from the heating and quenching apparatus 33.

Additional shielding means is also provided adjacent the inlet end of the heating and quenching apparatus 33 and, as shown in FIG. 8, takes the form of a water cooled shield 284 which is provided with an opening 286 to permit the steel members 31 to be heat treated to pass therethrough. The shield 284 is supported by the framework 121 as shown.

During the time that the member to be heat treated is passing through the heating and cooling apparatus, means is provided in the heating and quenching apparatus for providing forces to elongate the longitudinal surfaces of the member being heat treated to ensure that the member will be straight after it has cooled. This means consists of a large bottom pressure roller 291 which is shown particularly in FIG. 12. This roller 291 is adapted to engage the bottom of the member 31 being heat treated or, in other words, to engage a surface which is remote or opposite from the longitudinal surface being heat treated. The pressure roller 291 is mounted upon a shaft 292 which is rotatably mounted in bearings 293 affixed to arms 294. The shaft 292 with the pressure roller 29l mounted thereon is driven by a sprocket 295 affixed to the shaft 292. The sprocket 295 is driven by the drive chain 118 which is driven by the motor 106 as hereinbefore described.

One pair of ends of the arms 294 are pivotally mounted on the l-beams 127 by large bolts 296 which serve as fulcrums for the arms 294 (see FIG. 12). The other ends of the arms 294 are secured to a crossmember 298. As shown in FIG. 7, a clevis 299 is affixed to the crossmember 298 and is pivotally connected to a piston rdd 301 of a large fluid actuator 302. The

cylinder 303 of the actuator is mounted in a split bracket 304. The bracket 304 is provided with oppositely projecting pins 306 which form a trunion. A pair of connecting links 307 are pivotally mounted on the pins 306 and are also pivotally con' nected to a pair of arms 308 by pins 309 (see FIG. 12). The arms 308 are pivotally mounted on fulcrum pins 311 mounted in plates 312 secured to the I-beams 53. A shaft 313 is rotatably mounted in bearings 314 secured to the arms 308. A holddown pressure roller 316 is mounted on the shaft 313 and is adapted to engage the top surface of the member 31 to be heat treated.

From the arrangement shown, it can be seen that as fluid is supplied to the actuator 302, opposing forces will be applied between the

pressure rollers

291 and 316 to apply a bending moment to the steel member 31 to provide elongation of the longitudinal surface being heat treated as hereinafter described.

Stop means is provided for the arms 308 to limit the upward travel of the arms 308 and consists of capscrews 317 which are threaded into a crossmember 318 carried by members 319 secured to the I-beams 53. Lower stop means is also provided for the arms 308 and consists of posts 321 that are mounted upon the I-beams 53 and which are provided with adjustable capscrews 322. In addition to serving as means for limiting the lowermost position of the arms 308, the posts 321 also serve as means to prevent the arms 308 from dropping when no member is in position between the

rollers

291 and 316.

As hereinbefore explained, as bottom pressure is applied by the bottom pressure roller 291, downward pressure is applied by a top pressure roller 316 at the inlet end of the heating and quenching apparatus 33. As shown in FIG. 12, additional holddown means if provided at the outlet end of the heating and quenching apparatus 33 and consists of a roller 324 which is adapted to engage the top longitudinal surface of the steei member being heat treated. The holddown roller 324 is mounted upon a shaft 326 which is rotatably mounted in bearings 327 carried by upstanding members 328 affixed to the I-beams 127. Additional rollers 324 are provided as a part of the discharge conveyor assembly 34 and are mounted in a similar manner. A plurality of spaced support rollers 341 also form a part of the conveyor assembly 34 and are mounted.- between the I-beams 127 upon shafts 342 which are rotatably mounted in bearings 343 affixed to the I-beams 127.

The heating and quenching apparatus 33 also include, means for applying sidewise or lateral pressure to the steel members being heat treated for a purpose hereinafter described and consists of a pair of rollers 346 (see FIG. 13}. One of the rollers 346 is rotatably mounted in a housing 347 The housing 347 is pivotally mounted upon one end of one of the l-beams 127 by suitable means such as a bolt 348. The other of the rollers 346 is rotatably mounted in a housing 349 which is pivotally mounted on the other of the I-beams 127 by suitable means such as bolt 351. The housing 349 is provided with a lever arm 352 which is affixed to the housing 349 and which has its free end pivotally connected to a clevis 353 by a pin 354'. The clevis 353 is pivotally connected to a plunger 356 of a fluid actuator 357 by a pin 358. The cylinder 359 of the fluid actuator is affixed to a platform 360 (see FIG. which is affixed to the adjacent I-beam 127.

The two

pulley housings

347 and 349 are interconnected by a link 361 so that they move in unison. It can be seen that as the fluid actuator 357 is operated to apply a force to the arm 352, the rollers 346 engage the steel member and cause a bending force to be applied to the steel members 31 to introduce a curvature into the steel member or to ensure that all curvatures are removed from the steel members as hereinafter described.

A large strap 363 connects the ends of the l-beams 127 and prevents them from being spread apart during operation of the fluid actuator 357 which applies lateral forces to the steel members being heat treated.

As shown in FIG. 13, means is provided for limiting the lateral movement of the rollers 346 in both directions and consists of a pair of spaced blocks 366 mounted upon a plate 367 (see FIG. 12) which has one end secured to the platform 360 and which has the other end supported by a brace 368 affixed to the framework 121. A capscrew 369 is threaded into each of the blocks 366 and is provided with a lock nut 371 so that it can be locked in a predetermined position with respect to the arm 352. It can be readily seen that by adjustment of the capscrws 369, the maximum lateral movement of the rollers 346m either direction can be readily controlled.

Means is provided in the heating and quenching apparatus to ensure that as separate steel members travel through the heating and cooling apparatus they will stay in lateral and longitudinalalignment. As shown in FIG. 12 such means consists of a pair of rollers 373 which are adapted to engage the upper surface of the flange or base 31a (see FIG. 13) of the steel member 31 being treated. The rollers 373 are rotatably mounted upon bolts 374 which are fixed in upstanding members 376 secured to arms 294 by suitable means such as bolts 377. When the ends of two members pass through the apparatus 33, the rollers 373 ensure that the ends will be held down.

As hereinbefore explained, the holddown rollers 324 and the support rollers 341 form a part of the discharge conveyor assembly 34 and serve to receive the rails after they have been heat treated in the heating and quenching 3 apparatus. For reasons hereinafter explained, the steel member or members being heat treated will be cambered so that the forward or leading end of each section moves downwardly as indicated in FIG. 2. For this reason, the rollers 341 are provided at progressively lower positions between the I-beams 127 to accommodate this curvature of the steel members. Idler rollers 378 rotatably mounted on bolts 379 afiixed to the l-beams 127 are provided on opposite sides of the path of the steel members for guiding the steel members laterally as they are advanced along the conveyor assembly 34.

As'shown in FIGS. 6 and 11, supplemental means is provided for cooling the rails after they emerge from the heating and quenching apparatus and consists of a plurality of electrically operated blowers 381 which are mounted on opposite sides of a support pipe 382 extending longitudinally of and between the I-beams 127. The support rod is supported upon the upstanding members 328 by standards 383. The blowers 381 are provided with flexible nozzles 386 which, as shown, are inclined downwardly, forwardly and inwardly to direct streams of cooling air onto the heated steel member to further cool the heated steel member.

Still additional cooling air is supplied to the steel members just as they emerge from the heating and quenching apparatus 33 and consists of a tube 387 which is connected to the pipe 382. The pipe 382 is connected to a supply of air under pressure by the pipe 388 so that a stream of compressed air is continuously forced over the exterior surface of the steel member 31 just as it emerges. 1

The steel members 31, after they have been heat treated, are continuously advanced by the conveyor discharge assembly 34 until they arrive at the unloading station 35. A recess 391 (see FIG. 19) is provided in the foundation 392 at the unloading station to accommodate the camber in the steel members 31. A wearplate 393 is provided at the bottom of the recess and permits the steel members to .be readily advanced in the recess and into the unloading station."After the steel members have arrived atthe unloading station'jth'ey are raised by a suitable hoist 394 (FIG. 2) attachedto a davit 396 mounted on a hoist frame 397. The heat treated-steel members are then deposited on the shipping rack 36 which'consists of a plurality of spaced parallel reinforced frame members 398 which are provided with downwardly inclined surfaces 399 upon which rails 401 are mounted. i

As shown in FIGS. 1 and 2, a pair of stairways 403 are provided on opposite sides of the heating and quenching apparatus. They facilitate movement of operating personnel from one side to the other of the apparatus for the hardening of steel members. Safety railings 404 are provided in conjunction with the stairways 403. v

The use of my apparatus for the hardening of steel members in performing the present method or process may now be briefly described as follows. Let it be assumed that the steel members to be heat treated are steel r ail sections 31 ofa substantially conventional type in which the rails are formed with a base 31a, a web 31b and a head--131c(see FIGS. 13 and14). As hereinbefore explained, the steel members or rail sections 31 are taken from the receiving rack 29 and loaded oneby one by use of the loading station 30 onto'Fthe supply conveyor assembly 32 so that the leading edge of; each rail section 31 .engages the first powered roller v54 (the fourth from the leftas viewed in FIG. 1) which causes the rail section to be advanced along by the supply conveyor assembly ,32' in a predetermined path. As soon as the rail section 31 has beenadvanced sufficiently so that the trailing edge'of the rail section has cleared the first powered roller 54, another railsection is loaded onto the supply conveyor assembly 32 so its leading portion engages the first powered roller 54. i

As hereinbefore explained, the first powered roller5 4 is driven at a speed of rotation which is greater than the speeds of the other powered rollers54 so that the rail which has last been placed on the first powered roller 5 4 willquickly catch up with the preceding rail so that the leading faces of the rail sections are arranged end to end and engage the trailing face of the preceding rail. Thus, it can be seen the sections are continually in engagement with each other and that, in effect, there is provided a continuous rail in which the rail is pushed along the predetermined path formed by the supply conveyor assembly 32 rather than pulled.

As hereinbefore explained, additional driven rollers .54 are provided to advance the rails and each is driveri at aslightly slower speed of rotation so that the rail sections are continuously pushed. The clutch utilized for driving each of the powered rollers 54 permits slippage to occur in the clutch when the roller 54 requires more than a predetermined force to move the rail section with which it is in contact. This ensures that each of the rail sections will always be continuously pushed ahead with a predetermined force and maintained in contact with the preceding rail section so that the heating'and quenching apparatus 33. receives a steel member which," in effect, appears to be continuous and thereby permits the process utilized to be a continuous process with many attendant advantages as hereinafter explained.

As also hereinbefore explained, means is provided in the form of the side guide rollers74 and 76 for guidingthe steel members in a lateral direction in the predetermined path with the rollers or idlers 74 serving as a side guiding reference for the rails. The side guide rollers 76 are automatically positioned bythe actuators 81 to maintain therail sections in engagement with the sideguide rollers 74. The top guide rollers are also automatically, positioned by the actuators 92to maintain the rail sections in frictional engagement with therol lers 54 to thereby ensure that the rail sections will be positively" advanced along the predetermined path. i

Prior to the time that the steel members or rail sections 31 to be heat treated are advanced into the heating and quenching apparatus, the heating and quenching apparatus is placed in operation through the control panel 37. By operation of the control panel 37, fuel gas and oxygen are supplied to the burners 133 of the heating assembly 131 and the burners are ignited. At approximately the same time, the burners 247 of the bottom heating assembly 246 are also supplied with fuel gas and oxygen and ignited. 7

Prior to ignition of the

burners

133 and 247, cooling water is supplied to the burner heads. This cooling water can be obtained in any suitable manner. In the present apparatus, it has been found desirable to utilize a closed system for the cooling water in which the cooling water, after it is returned from the burners, passes into the converter 39 and flows over pipes (not shown) in the converter and back to the burners. The pipes in the converter 39 are connected to the liquid oxygen tank38 and are utilized for gasifying the liquid oxygen before it is supplied to the burners. The liquid oxygen, inbecoming gasifled, cools the water and serves to remove -the.heat which previously had been absorbed by the water when it passed through the. burners and other-"water cooled parts of the apparatus hereinbefore described. Such a system has been found to be very economical because only a small water supply is required. This is particularly important where it is desired that the apparatus be portable.

The fuel gas utilized in the burners may be of any suitable type. The apparatus works very satisfactorily utilizing less expensive gases such as natural gas, butane or propane. Such gases, as is well known to those skilled in the art, when burned with oxygen give a temperature ranging from approximately 4500 to 4600 F. By the use of the specially constructed burners hereinbefore described and with the use of the fuel gas under a substantial pressure, it is found that very adequate heat can be obtained from such a mixture. For example, it is possible to operate the apparatus very successfully with fuel gas pressures ranging from S to 30 p.s.i.

As described, the burners 133 are positioned side by side to, in effect, provide a very large burner having its longest dimension extending longitudinally of the path of travel of the rail. In the embodiment shown, each of the burners 133 is provided with 130 ports so that each of the burners provides 130 jets of flame so that with the eight burners shown, 1040 jets of flame are provided which give a great mass of highly concentrated heat which, however, is very uniformly distributed over the longitudinal surface of the steel member being heated.

At the same time that the burners are started, air under a ressure ranging from 25 to 150 psi. is supplied to the devices 133 which form the quenching assembly 132 so that a large volume of air is jetting from the large number of ports provided in the quenching assembly 132 in the form of a multiplicity of jets evenly distributed over a relatively large area having its longest dimension extending longitudinally of the path of travel ofthe rail. The blowers 381 are also placed in operation and compressed air is also supplied to the pipe 382 so that air is jetting from the tube 387.

Afier the heating and quenching apparatus has been placed in operation, the rail 31 is advanced beneath the hold-down roller 316 and over the support roller 54 immediately below and thence into the intense, highly concentrated heat which is present in the recesses 212 provided in the burners 133. As hereinbefore explained, the recesses 212 in the burner heads 134 are formed so that they have a configuration which generally conforms to the configuration of the upper portion 14 Because the burners 133 envelop the head of the rail, there will be some exhaust or residual heat which will be forced downwardly along the web 31b (see FIG. 14) of the rail and downwardly over the base 31a (see FIG. 12) of the rail'and then deflected outwardly onto the firebrick 282 where it is deflected upwardly and outwardly away from the heating and quenching apparatus so that the burners and other parts of the apparatus are not damaged by the heat. This heating of the web and base of the rail is beneficial because it reduces the camber placed in the rail during heat treatment and also prevents theformation of residual stresses within the rail.

During the time that the rail head is'passing through the heating zone formed by the heating assembly 131, the longitudinal surfaces and portions of the rail head being heat treated are raised to a temperature within or above the critical range in order to convert the surfaces or portions partially or completely to austenite.

After the longitudinal surfaces have been heated as hereinbefore described, the rail is advanced to move the heated surfaces into the quenching zone formed by the quenching assembly 132 wherein the heated surfaces and portions are rapidly cooled by the multitude of small jets of air uniformly distributed over the longitudinal heated surfaces. The heated surfaces are cooled to a temperature range for martensitic formation at a rate equal to or faster than the critical cooling rate of the steel being heat treated to obtain the desired hardness.

Because of the conformation of the quenching devices, air is also directed downwardly over the web and the base to cool the same. However, hardening does not take place because the web and base were not heated to or within the critical temperature. As the rail is advanced out of the heating and cooling apparatus, the rail is still further cooled by jets of air from the tube 387 and from the blowers 381.

During the time that the longitudinal surfaces are still hot, bottom pressure is applied to the bottom of the steel rail by the roller 291. This is applied by supplying fluid to the fluid actuator 302 which pulls up on the roller 291 and pulls down on the roller 316 The pressure applied by the bottom pressure roller 291 is sufficient to cause the rail head 31c to yield or stretch a predetermined amount. This stretching of the rail head while it is hot is performed so that the rail will be perfectly straight when it has cooled to the ambient temperature as explained below.

It is well known that when one longitudinal surface as, for example, the head of a rail is heated to a much higher temperature than the other portions of the rail, a bow or camber will be placed in the rail. lt is believed that during the time this bow or camber is formed in the rail, the heated head of the rail section is compressed because of the great amount of force which is required to deform the other cool portions of the rail section. This is believed to be true because when the rail section cools after it has been bowed in this manner, a reverse camber appears in the rail and the ends of the rail sections are turned up.

During the time that the head of the rail section is still quite hot, this reverse camber can be avoided by actually stretching the head of the rail section, i.e., the longitudinal surfaces being heat treated, and in that manner placing a greater camber in the rail section than would normally be the case if the rail section were merely heated without pressure being applied thereto. Because the stretching of the head of the rail is performed at the time it is heated, no residual stresses are set up in the rail section. This is also true because, as hereinbefore explained, the web and the base of the rail are also heated to some degree. After the rail is finally cooled, the contraction of the steel in the rail head pulls the rail back into a final, perfectly straight section.

As can be seen from FIG. 12 of the drawings, the amount of actual deformation of the rail is relatively small. However, relatively large forces as, for example, 40 to 60 tons pressure, must be applied by the bottom pressure roller 291 to accomplish the desired stretching of the head of the rail during the time it is hot. This bottom pressure is continuously and progressively applied to the base of the rail as the rail is advanced through the heating and quenching apparatus. From the arrangement shown, it can be seen that the bottom pressure roller 291 is positioned between the

top rollers

316 and 324 so that there is no danger of damaging the burner or quenching apparatus by upward pressure.

As hereinbefore described, the heating assembly 131 and the quenching assembly 132 actually float or travel upon the rail head in such a manner that the burner heads and the quenching heads follow the rail head very closely and are spaced a predetermined distance from the rail head during travel of the rail through the heating and quenching apparatus 33. The rollers 373 ensure that when ajoint between two rail sections passes through the heating and quenching apparatus the rail sections are still maintained in alignment in the apparatus.

Pressure is not applied by the bottom pressure roller 291 until the leading edge of the rail section engages the first top roller 324. Pressure is then applied by operation of the actuator 302. When the trailing edge of a rail section clears the top roller 316 pressure from the bottom pressure roller 231 is removed by operation of the actuator 302. Thus it can be seen that bottom pressure is only applied when the rail section is in engagement with both

top rollers

316 and 324 on opposite sides of the bottom pressure roller 291. In order to ensure that the rails will be perfectly straight after they have cooled to the ambient temperature even though bottom pressure is not applied when the extreme ends of the rail section are being heat treated, 1 have found that it is desirable to add some heat to the leading and trailing ends of each rail section. Thus, bottom heat is applied to the leading and trailing ends of the rail section after they pass over the bottom pressure roller 291. Otherwise, the bottom pressure roller could possibly deform the base of the rail section. It has been found desirable to apply bottom heat to the first to inches of each of the leading ends of each rail section through the bottom burner assembly 2%. This bottom heat aids in the expansion of the base. As soon as the first 20 to 30 inches of each rail section have passed over the bottom burner section and the rail section has engaged the first top roller 324, bottom pressure from the roller 291 is applied and the bottom burner assembly is turned off. As soon as the trailing end of the rail section clears the roller 316, bottom pressure from roller 291 is removed and the bottom heating assembly 246 is again turned on to heat the last 20 to 30 inches of the base of the rail section. This heating of the ends of the rail section ensures that the ends of the rail section will not turn up when the rail section cools to ambient temperature. Thus, even though no force is applied to the extreme ends of each rail section by the bottom pressure roller 291 to cause elongation of the surface being heat treated, perfectly straight rail sections are obtained by heating the base portions of the ends of the rail sections.

On certain occasions, it may be desirable to apply lateral pressures to the steel member while it is in the heating and quenching apparatus 33 as, for example, when there appears to be a lateral bow in the steel members and it is desired to straighten the same or, for example, when it is desired to place a bow in a steel rail as, for example, when producing curved rail sections. This is accomplished by supplying fluid under pressure to the double acting hydraulic actuator 357 to cause a lateral force to be applied in one direction or the other to the rail or steel member being hardened. Although this step is shown being performed during the time that the steel member is passing through the quenching heads, it is readily apparent that, if desired, this operation or step can also be performed anytime during the time that the steel member is passing through the heating and quenching apparatus while it is still hot.

The rail sections, after they have been heat treated and cooled, are advanced by the discharge conveyor assembly 34 to the unloading or shipping station where they are picked up and loaded onto the receiving rack where they can cool down to the ambient temperature. The camber is lost as soon as the rails have cooled down to the ambient temperature. No restraightening is required. The rails are perfectly straight and ready for use. By way of example, 1 have found it feasible to produce repeatably with my method and apparatus hardened rail sections in which rail sections 39 feetin length would not be over one-eighth inch off from being perfectly straight.

The apparatus and method for the hardening-of steel is very advantageous because it can be operated continuously. This makes it unnecessary to turn off the top heating'assembly 131 and the quenching assembly 132 which, therefore, makes it possible to obtain great uniformity in the heating and quenching of the steel members.

The construction of the burners is such that it is possible to supply great quantities of heat at sufficiently low temperatures so that there is no surface damage to the steel or any variation created in the grain structure of thev steel. The heat supplied by the burners is actually balanced with the ability of the steel to absorb the heat so that the steel members can be heat treated to any desired depth without any danger of surface damage to the steel. The depth of penetration of the heat is primarily controlled by the rate of movement of the steel member through the heating and quenching apparatus. Thus, when it is desired to increase the depth of the hardness zone of the steel members, it is merely necessary to decrease the rate of travel of the steel members through the heating and quenching apparatus. The hardness desired can also be readily changed merely by changing the quantity of air supplied by the quenching assembly 132. When it is desired to increase the hardness, the air passed over the heated surface of the steel member is increased and, conversely, when a lower hardness is desired, the amount of air passing over the heated steel member is decreased. This can be readily accomplished merely by increasing or decreasing the air pressure.

By the use of the apparatus and method hereinbefore described, 1 have found that it is possible to obtain hardened steel members of greatly improved quality over that which can be obtained with conventional apparatus and methods. By way of example, there is shown in FIGS. 20A and 20B cross sections of rail hardened in my apparatus with my method. in FIG. 20A, there is shown a hardened zone 411 of approximately three-eighths of an inch in depth which envelops the head of the rail. The hardened zone extends across the top of the rail head and downwardly along the side edges of the rail head to provide a hardened cap on the rail head with the hardness indicated in Rockwell C" scale, and in Brinellin the middle of the hardened zone and on one of the corners. As can be seen, the hardened zone 411 has a substantial depth which serves to prevent the hardened cap on the rail head from being rolled or shelled off. The hardened zone decreases quite slowly in hardness from the outer surface, and then there is a gradual transition in hardness to the original structure of the head to, in effect, provide a transition zone 412 of substantial thickness. This deep transition zone 412 increases resistance to shelling and helps to eliminate any residual stresses in the rail after it has been hardened.

1n the hardening of rail, it is generally desirable to raise the surface hardness of the head of the rail by approximately points of Brinell above the original normal hardness of the rail. As can be seen from F1G. 20A, this has been readily accomplished. It will be noted that the corners of the hardened zone are slightly harder than the middle of the hardened zone. This is because the corners are heated more rapidly and quenched more rapidly. This is a desirable feature insofar as rails are concerned because the comers usually receive more wear than do the other portions of the rail head.

In FIG. 208, the hardened zone 411 has a depth of approximately one-half of an inch. Again, the hardness zone extends across the top of the head and down the sides. A rather deep transition zone 412 is also formed.

In general, as can be seen from FIGS. 20A and 208, planes of substantially uniform or equal hardness parallel to the outer surface of the head of the rail are formed in the hardened zone of the rail head. In other words, there is very little variation in

Claims

2. Apparatus as in claim 1 wherein said heating means includes a plurality of burners, each of said burners having a burner face with a cross section conforming generally to the configuration of the lateral cross section of said longitudinal surface to be heated and having a plurality of relatively closely spaced ports formed therein with flames jetting therefrom and impinging upon said longitudinal surface at substantially right angles to said longitudinal surface, said ports being substantially uniformly distributed over a portion of said longitudinal surface.
3. Apparatus as in claim 1 wherein said quenching means includes a device having a face plate with a cross section conforming generally to the configuration of the lateral cross section of said heated longitudinal surface and having a plurality of closely spaced ports therein substantially uniformly spaced over a portion of said longitudinal surface, together with means for supplying air under pressure to said device, the air jetting from said ports and impinging upon said heated longitudinal surface at substantially right angles thereto.
4. Apparatus as in claim 1 together with means for further cooling said metal member after it has passed from the heating and quenching means.
5. In apparatus for the hardening of a longitudinal surface of an elongate metal member, a heating means including burners and a quenching means, means for advancing the metal member at a predetermined rate along a predetermined path and through the heating and quenching phases of said means, the heating assembly progressively heating a longitudinal surface portion of the metal member as it is advanced through the heating assembly to raise the longitudinal surface to or within the critical temperature range whereby the heated surface portion expands and causes a camber to be formed in the member, the quenching means progressively quenching the heated longitudinal surface portion of the metal member as the metal member is advanced, means including a pair of rollers one engageable with said longitudinal surface after said surface has been heated and quenched and the other engageable with the side of said elongate member opposite said surface and adjacent said heating assembly for applying opposite forces to the member while it is being heated to or within the critical temperature range in directions perpendicular to the camber so that the camber in the member is increased and the heated longitudinal surface expanded, means for simultaneously moving the axis of each of said rollers toward the longitudinal axis of said elongate member, said heating and quenching means including a source of liquid oxygen, a converter, a supply of water disposed in said converter, means for circulating the liquid oxygen through the water in said converter to convert the liquid oxygen to gaseous oxygen, means for supplying the gaseous oxygen to said burners, means for supplying fuel gas to said burners, means for supplying cooling water from said converter to said burners for cooling said burners, and means for returning the cooling water to said converter after it has been supplied to said burners.
6. In apparatus for the hardening of a longitudinal surface of a metal rail member having head and base portions, a heating assembly including burner means, a quenching assembly, means for advancing a plurality of metal rail members end to end along a predetermined path through said heating and quenching assemblies, said heating assembly serving to progressively heat a longitudinal surface of said rail member as it is advanced through said heating and quenching assemblies and serving to heat the surface to or within the critical temperature range, said quenching assembly serving to progressively quench said longitudinal surface after it has been heated by said heating assembly, the heating of said longitudinal surface of said metal rail member serving to place a camber in said rail member, and means for progressively applying a force to each rail member perpendicular to said longitudinal surface to increase the camber in said rail member and to cause elongation of the heated surface of said rail member while the heated surface is still hot whereby when said rail member has cooled to ambient temperature said metal rail member will have a predetermined shape, said burner means including first burners spaced from but disposed adjacent to the top longitudinal surface of said head portion to be heated, said burner means also including additional burners disposed on the bottom side of said base portion opposite said first burners.
7. In apparatus for the hardening of a longitudinal surface of a metal rail member, a heating assembly including a plurality of burners, each of said burners comprising a housing, means dividing said housing into two chambers, a portion of said housing forming a burner face conforming generally in cross section to the lateral cross section of the longitudInal surface of said rail member, a quenching assembly, means for advancing a plurality of metal rail members end to end along a predetermined path through said heating and quenching assemblies, said heating assembly serving to progressively heat a longitudinal surface of said metal rail member as it is advanced through the heating and quenching assemblies and serving to heat the surface to or within the critical temperature range, said quenching assembly serving to progressively quench said longitudinal surface after it has been heated by said heating assembly, the heating of said longitudinal surface of said metal rail member serving to place a camber in said metal rail member, means for progressively applying a force to each metal rail member perpendicular to the longitudinal surface to increase the camber in said rail member and to cause elongation of the heated surface of said rail member while the heated surface is still hot whereby when said metal rail member has cooled to ambient temperature said metal rail member will have a predetermined shape, a plurality of tubes in each of said burners extending from one of said two chambers through the other of said chambers and through said burner face, means for supplying a combustible mixture under pressure to said first chamber so that said mixture will pass through said tubes and burner face and be combusted, and means for supplying a cooling fluid to the other of said chambers to cool said burner face.
8. Apparatus as in claim 7 wherein said burners are formed with flat sides thereby permitting said burners to be placed in juxtaposition.
9. In apparatus for the hardening of the head of a plurality of rail sections in which each of said rail sections has a head and a base interconnected by a web, a heating means and a quenching means, a supply conveyor leading into the heating and quenching means, a discharge conveyor leading from the heating and quenching means, said conveyors forming a predetermined path through the heating and quenching means, means for loading rail sections onto the supply conveyor one by one, said supply conveyor including means for advancing the succeeding rail sections at a greater rate than the preceding rail sections so that said rail sections are continually pushed with their ends abutting and are advanced in line in a predetermined path through the heating and quenching means in end-to-end abutment, means for applying a force to a portion of said rails while said portion is under the influence of said heating and quenching means to cause elongation of the head of the rail while the head of the rail is at or within the critical temperature range, said last mentioned means comprising a framework, a pair of arms pivotally mounted on said framework, a first roller rotatably mounted by said arms for engaging the base portion of said rail while said portion of the rail is within the influence of the heating and quenching means, a pair of rollers engaging the heads of said rail sections, a pair of additional arms mounted on said framework, means rotatably mounting one of said additional rollers in said pair of arms, an actuator, means connecting the free end of said first named arms to the actuator, means connecting the free ends of the additional arms to said actuator, and means supplying fluid to said actuator to apply opposing forces to said first named and additional arms for simultaneously moving the axis of the first roller and said one of said additional rollers toward the longitudinal axis of said rail sections to cause said first roller to apply pressure to the bases of the rail sections as they are being advanced through the heating and quenching means while at the same time causing opposing forces to be applied by the other rollers, said first roller being mounted in the heating and quenching means so that it applies a pressure to the portion of the rail section that is being heated and wherein the additional rollers are mounted away from the portion of the rail section that is Being heated, and means for removing the quenched rail sections from the discharge conveyor at a temperature below said critical range.