US1712833A - Apparatus for heat treating and quenching bar stock - Google Patents

Description

y 14, 1929 J. .1. MASCUCH 1,712,833

APPARATUS FOR HEAT TREATING AND QUENCHING BAR STOCK Original Filed Feb. 23, 1926 j :A TTORNEY.

Patented May 14, 1929.

UNITED STATES PATENT OFFICE.-

J'OSEPH J". MASCUCI-I, OF EAST ORANGE, NEW JERSEY.

Application filed February 23, 1926, Serial No. 89,986. Renewed December 14, 1928.

This invention relates to a process of heattreating and tempering bar steel such as used in automobile bumpers and thelike and has for an object to reduce the cost of manufacture and to improve the final product.

In the manufacture of bumpers and the like from bar steel stock which has to be tempered after forming, the established practice is to take the bar as it comes from the rolling mill, cut it into suitable lengths, pickle it in acid to remove the rust and it may be ground to remove the scale. It is then heated and bent to form, sometimes requiring several heats for this purpose. After manufacturing to form, the bar is heated throughout its entire length to as nearly a uniform heat as possible and then quenched in oil at a regulated temperature. When cool the bar is drawn out of the oil and is very hard and brittle and is not usable until the temper is drawn to reduce the hardness and increase its elasticity. For this purpose it is put through a drawing oven r at a temperature of approximately 850 F for a period of minutes. This anneals the metal and makes it tough and springy.

Tn the process described it is found that the drawing oven has an oxidizing effect on the surface of the bar promoting the formation of scale, it is also found that the oil quenching leaves a carbon adhesion on. the bar which can be removed only by abrasion. This is particularly true in the case of oils having animal fats which are readily carbonized and it bgzomes more pronounced as the specific gravity of theoil changes.

The oil used for tempering purposes is. to a certain extent, volatile, and as the heated bars are immersed in this oil it is readily vaporized creating disagreeable fumes and rapidly changing the specific gravity of the oil so that its harmful ingredients become more pronounced. For the same reason it is not possible to heat the oil above a fixed temperature which chills the metal during the tempering process to a brittle hardness as described.

T have found by experiment that bar stock of this class can be tempered and heattreated in water by one heat in a few seconds of time by the use of an automatic regulated mechanism which regulates the temperature of the stock to be tempered, regulates the temperature of the quenching fluid and regulates the time of immersion. In carrying out this process the bar is heated and manufactured to shape as desired. It is then heated throughout to a uniform temperature of 1475 F. which may be done electrically, and immersed in water at a temperature of between 155F. and 165 F. for a period of approximately 20 seconds; this time depending upon the temperature of the bar and its carbon content.

The water is maintained at an even te1nperature by thermostatic control which automatically supplies cold Water or steam 'to the water tank as the water temperature rises or falls with relation to the predeter mined temperature. The arrangement eveply distributes this water throughout the tan I.

It is found in practice that by carefully regulating the time of immersion the chilling of the bar may be suspended so that it is withdrawn from the water retaining sufficient heat for its own annealing and a bar is produced having the same characteristics under tests as the bars heat-treated and tempered in oil and the process is carried out in a fraction of the time, with fewer operations and at much less expense, and without the scale produced by the free carbon of the oil. This process not only eliminates the drawing operation but it can be satisfactorily used on steel bars having a carbon content from to 90 point by the proper regulation of the Water temperature and the initial heat of the bar.

The process of this invention may be carried out by the use of the machine shown in the accompanying drawings, in which, Fig. 1, is an elevation of a tempering machine having attachments thereon suitable for carrying out this process and Fig. 2 is a plan view of the cradle carrying the stock to be tempered and fitted with an electric heating arrangement.

A tank 11 is provided with a water acket 0; and in which the Water may be kept circulating by the pipes 12 and 13. This water jacket may be used to maintain an even temperature in the immersion tank 79 which contains the tempering fluid, usually water or oil. Rising from the tank I) are the side frames 14 and 15 of the tempering machine by which the cradle 16 is raised and lowered through a predetermined time interval hereafter described. On this cradle the bars 17 of insulating material are placed to support the bar stock 18 which is to be operated upon.

The cradle 16 is suspended from the rack bar 19 which is engaged by the pinion 20 and by the rack bar 21 which is engaged by the pinion 22. These pinions are mounted on shaft 23, which, through the gears 24 and 25 is driven by the shaft 39. The shaft 39 has two driving connections, one includes the spur gears 37 and 38, sleeve 36 and clutch member 35. The other drive includes spur gears 42, 43 and 44, the sleeve 41 and the clutch member 40.

The driving motor 31 through the worm gear 32 drives shaft 33 in a particular direction and upon this shaft the clutch 34 is splined. It is apparent that when clutch 34 is moved to the'right as shown, sleeve 36 rotates with shaft 33 while the sleeve 41 is idle. This will drive shaft 23 in a predetermined direction and may be arranged to lower the cradle into the immersion fluid.

VVhen the clutch 34 .is moved to the left,

'idler gear 43 sleeve 41 rotates shaft 23 in a direction opposite to sleeve 36 and may be arranged to raise the cradle from the immersion fluid. Thus the up and down movement of the cradle is regulated by the clutch 34.

The clutch 34 is controlled by the regulating motor 57 which, through the worm 58 drives the cam having the cam grooves 51 and 52 as shown. A lever 48 pivoted at 49 has the upper end engaging the groove of cam 51 as at 54 and a connecting rod 47 is pivotally connected to this lever at 55 andoperates the clutch lever 45 which is pivoted at 46. With this construction it will be observed that the clutch 34 is moved to the right or to the left in response to the groove 51 of the cam 50 and the speed of cam 50 is regulated by the speed of motor 57. The time of immersion can thus be regulated by the shape of the cam and by the speed of motor 57 relative to the up and down movement of the cradle. Thecam 50 may be provided with a plurality of grooves of different shapes as the groove 52, to which the rod 48 may be transferred in which case the connecting rod 47. is pivoted at 56 to the lever 48.

The .tank 6 is artificially heated by the reverse arrangement may be used to admit water to the water jacket when the temperature is above a predetermined value. The thermostat thus acts to maintain an even temperature in the tempering fluid which,

in co-operating with the timing arrangement for the movement of the cradle. secures a definite and predetermined tempering effect producing a uniform condition in the stock.

The bar stock may be heated in an ordinary furnace for applying this process. However the present arrangement provides for heating the bars by the use of the electric current. The transformer 78 connects by Wire 77 to the bus bar 71 and by wire 76 to the bus bar 72. The contacts 73 are connected to the bus bar 71 and the contacts 75 are connected to the bus bar 72. The ends of the bars 18 are connected in circuit between these contacts so that the current from the transformer heats the bars uniformly throughout. The circuit of the transformer may be manually controlled by a hand operated switch. It is desirable and in fact necessary that the heating current be automatically controlled so that the circuit will be interrupted just before the immersion'of the bars. This is secured by the switch 0 in the circuit of wire 76 which is mounted on the frame 14 and is provided with an operating lever 81 which is engaged by the pins 82 and 83 in the rack bar 19 so that the switch lever 81 is moved up and down with the movement of the cradle 16. The downward movement of 81 interrupts the circuit and the upward movement closes the circuit. The pins 82 and 83 may be adjustably located in the bar 19 to secure a relative adjustable operation of the switch lever 81.

With this arrangement the heating and tempering is performed by a single mechanism. The bar stockmay be fed to the machine by hand or by an automatic arrangement of feed which is not contemplated in the present application. The machine operates automatically to control the heating of the stock, to regulate the temperature of the tempering fluid and to regulate the time of immersion. This simplifies the operation of tempering and heat-treating and saves time.

Having thus described my invention, I claim:

1. In a machine for tempering bar stock, the combination of a support for the stock, means for heating the stock by an electric current on said support to a uniform temperature, an immersion fluid, means for immersing said stock in said fluid for a time interval, means for controlling said time interval and means for automatically interrupting said current before immersion takes lace. p 2. In a machine for tempering bar stock, the combination of a cradle supporting the automatically regulated to operate in a fixed time interval for immersing said cradle in said fluid.

4, In a machine for tempering steel stock, the combination of a cradle carrying the stock and having means for heating the stock by an electric current, a switch controlling said current, an immersion fluid, an automatically regulated mechanism for immers-- ing said cradle in said fluid and means for automatically operating said switch to interrupt said current before said stock is immersed,

5. In a machine for tempering bar stock, the combination of an immersion tank, a cradle vertically slidable above said tank, a rack and pinion associated with said cradle for moving it up and down, said cradle supporting the stock and having means for heating the stock and means for automatically controlling said rack and pinion movement.

6. In a machine for tempering bar stock, the combination of an immersion tank, a cradle vertically slidable above said tank, a rack and pinion and a clutch associated with said cradle for moving it up and down, said cradle supporting the stock and having means for heating the stock and an independently controlled cam for operating said clutch.

7. In. a machine for tempering bar stock,

cradle movable into and out of said tank and supporting the stock and having means for heating the stock and a timing mechanism for controlling the movement of said cradle. v

8. In a machine for tempering bar stock, the combination of a cradle carrying the stock and having means for heating the stock by an electric current, an immersion tank for said cradle, means for moving said cradle into and out of said tank, a switch for controlling said current and adjustable means operated by said cradle for operating said switch.

9. In a machine for tempering bar stock, the combination of an immersion tank, a cradle movable into and out of said tank supporting the stock and having means for heating the stock, a mechanism controlling the movement of said cradle and a motor operated cam controlling the operation of said mechanism.

10. In a machine for tempering bar stock,

the combination of an immersion tank, a r

the combination of an immersion tank, a

cradle movable into and out of said tank supporting the stock and having means for heating the stock, a mechanism controlling the movement of said cradle and adjustable means for controlling the operation of said mechanism.

Signed at VVilkes-Barre in the county of Luzerne and State of'Pennsylvania, this 4th day of June. 1925.

JOSEPH J. MASCUCH.

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