US3672877A - Corrosion-resistant razor blades - Google Patents

Corrosion-resistant razor blades Download PDF

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Publication number
US3672877A
US3672877A US64087A US3672877DA US3672877A US 3672877 A US3672877 A US 3672877A US 64087 A US64087 A US 64087A US 3672877D A US3672877D A US 3672877DA US 3672877 A US3672877 A US 3672877A
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Prior art keywords
steel
chromium
steels
hardness
carbon
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US64087A
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English (en)
Inventor
Jan-Christer Henric
Claes Bertil Bergqvist
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Santrade Ltd
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Sandvik AB
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Assigned to SANTRADE LTD., A CORP. OF SWITZERLAND reassignment SANTRADE LTD., A CORP. OF SWITZERLAND ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SANDVIK AKTIEBOLAG, A CORP. OF SWEDEN
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium

Definitions

  • the present invention relates to improvements in corrosion-resistant steel razor baldes.
  • they have a high cutting edge hardness and a structure free from deleterious carbide grains.
  • the cutting edge hardness exceeds 800 Vickers (0.5 kg. load) (VPN 800) after the hardening of the steel, and 720 Vickers (VPN 720) when tempered up to 450 C. subsequent to the hardening.
  • the invention also comprises a method of manufacturing such, blades.
  • the steels of type A when hardened to a hardness close to 800 Vickers assume a structure including a large number of coarse carbide grains within the range of 3-30 micron (maximum linear dimension) which render it impossible to obtain a smooth cutting edge on a tool of this steel, as these grains are easily torn out during the grinding of the cutting edge and give the edge a frayed contour and surface.
  • the corrosion resistance of these steels is only moderate.
  • Steels of the type B have less coarse carbide grains and a somewhat better corrosion resistance than have the steels of the forementioned type, but the maximum hardness obtained by hardening is less than that for type A, which adversely influences the duration of edge sharpness of the blades manufactured from the same.
  • the purpose of the present invention is to provide corrosion-resistant blades such as razor blades having an improved corrosion resistance in combination with superior edge sharpness and smoothness and improved temper resistance.
  • the appended drawing is a schematic diagram showing the preferred contents of carbon and the sum of chromium, one-half of the molybdenum and one-quarter of the tungsten of a steel composition exemplary of the present invention. Said sum is designated Y in the diagram.
  • the razor blades are made from a steel having a very good corrosion resistance and a hardness exceeding 800 Vickers (load 0.5 kg.) (VPN 800) in the hardened condition and a hardness after tempering up to 450 C. exceeding 720 Vickers (VPN 720) and being within the range 720-850 Vickers (VPN 720- 850) depending on the tempering temperature.
  • the steel which has good workability, such as excellent cold rolling properties, is characterized in that it contains 0.300.50% carbon; 9-11.5% chromium; 0.8 2% silicon; 01.0% manganese; 0l.5% molybdenum; 03.0% tungsten and 0.1% each of a member of the group consisting of nickel, cobalt, copper, niobium, tantanium, vanadium, zirconium, boron and berryllium, the total of all the last said members being a maximum of 1%; and the remainder being substantially all iron, and in which the carbon and the sum of the chromium, one-half of the molybdenum and one-quarter of the tungsten are present in amounts which are defined Within the area ABCDEFA in the accompanying diagram, wherein the said sum is designated Y.
  • the chromium contentand, molybdenum and/or tungsten are present, the sum of the chromium content, onehalf of the molybdenum content and one-quarter of the tungsten contentshould also be low.
  • the limiting conditions defined by the co-ordinates of the area ABCDEFA are the following: A, /03; B, 11.25/03; C, 12.25/04; D, 12.25/05; E, 10.0/0.5; and F, 9.0/0.4.
  • the carbon content should not exceed 0.45%, e.g., be within the range 0.35-.45%.
  • the chromium content should as a rule be held within the range 9.25-11.0%, and preferably -11%.
  • the sum of the contents of chromium, one half of the molybdenum and one-quater of the tungsten preferably should be held within the range 9.51l.75%.
  • the preferred amount of carbon and the sum designated Y of the amount of the chromium, one-half of the amount of molybdenum and one-quarter of the amount of tungsten are defined within the area A B C D E F A in the accompanying diagram in which the co-ordinates are the following: A 9.5/0.35; B 11.25 0.35; C 11.75/0.40; D 11.75/0.45; E 10.0/0.45; F 9.5 0.40.
  • the content of molybdenum should normally be chosen within the range 0.3-1.5 Often it should exceed 0.5 and a preferred range is 0.71.3%.
  • the content of tungsten preferably should be, at the most, 2.6%.
  • the silicon content preferably should be 0.9%-1.5% and the manganese content 0.20.7%.
  • the amounts of each element of the group consisting of nickel, cobalt, copper, niobium, tantalum, titanium, vanadium, zirconium, boron and beryllium normally should not exceed 0.5%, and the total of all these elements should also not exceed 0.5%.
  • the composition should be balanced in such a way that the analysis of the steel and that of the matrix are substantially the same.
  • One of the advantages gained by the steel according to the invention is that the composition of the matrix after hardening will be practically constant irrespective of changes in the hardening conditions. This means that also the corrosion resistance will be unchanged and that the steel is insensible to changes in the heat treatment conditions. Due to the relatively low contents of carbon and chromium present in the steel of the present invention the steel is practically free from primary carbides, which circumstance is of great importance for the achievement of excellent cutting blades. In the hardening of the steel any carbides present are practically completely dissolved whereby the chemical analysis of the matrix will be the same as the analysis of the steel.
  • composition of the matrix decides the corrosion resistance of the hardened steel contributes to the excellent corrosion resistance of the steel according to the present invention.
  • a further advantage in comparison with the previous corrosion-resistance steels is the lower content of chromium which is of importance with respect to costs.
  • the hardness of the steel depends on the carbon content of the steel. However, if the M,,-temperature of the steel i.e., the temperature when the transformation of austenite into martensite beginsis unduly lowered by the addition of too high amounts of alloying elements to the steel, the austenite transforms only partly into martensite with the result that the hardness will not be sufficiently high even if a martensite-promoting low-temperature cooling is practiced.
  • the prior steels used for the manufacture of corosion-resistant edge tools such as razor blades have not had compositions conveniently balanced and hence the maximum hardness reached by these steels has been considerably less than wanted. Nor has it been possible by these steels to obtain such a uniform composition in the matrix as in the steel according to the present invention. Thus the presence of large amounts of carbide grains in said prior steels gave rise to variations in the chemical composition around the grains, which in turn reduced the maximum hardness obtainable by hardening.
  • the structure of the steel as cold-rolled is of considerable importance for producing an excellent edge.
  • the presence of coarse carbide grains is a serious disadvantage, as they (as was earlier mentioned) are easily torn out during the grinding of the cutting edge and give the edge a frayed contour and surface.
  • steels A and B represent previously used razor blade steels while the steels C1 and C2 represent steels according to the invention.
  • the hardness of corrosion-resistant chromium steels depends on the temperature used for the hardening, the cooling from the hardening temperature and the tempering temperature. For steels which contrary to the steel according to the invention-do not have a balanced composition, there is always by a fixed hardening time and a fixed cooling method only one hardening temperature, which gives maximum hardness. By subsequent tempering at 100-150" C. it is possible somewhat to increase said hardness.
  • the higher hardness of the steels according to the invention facilitates edge grinding, improves the edge quality and contributes also to a prolongation of the useful life of the edges ifas is common-the edges are coated with a fluorocarbon or other material for enhancing the shaving characteristics, in which event the blades as a rule are tempered at a temperature within the range 200-400 C.
  • the final edge hardness depends on the temper resistance of the steel when tempered within said range.
  • a comparison of the temper resistance of the prior steels A and B and the steels C1 and C2 according to the invention when tempered at 350 C. is made in the table below:
  • the invenion also relates to a method for the manufacturing of razor blades from steels according to the invention.
  • the steel is cold rolled in strip form to the desired thin dimension, e.g., 0.05-0.5 mm., after which a shaping, e.g., punching, may be done.
  • the cold-rolled steel strip is then hardened to high hardness by heating to a temperature within the range 1050-1125 C., preferably about 1100 C., with subsequent cooling to room temperature or lower, e.g., in the range between -20 C. and 120 C.
  • the cutting edges are shaped by grinding or the like.
  • the material may be tempered during a limited period of time, for instance, for about a minute up to one or a few hours, at a temperature up to 450 C., e.g., within the range ZOO-400 C.
  • the hardness of the steel after said final tempering is at least 700 Vickers (VPN 700) and lies within the range 720-850 Vickers (VPN 720-850) when tempered between 200-400 C., depending on the temper temperature.
  • the razor blades being made from a steel consisting of in part by weight, 0.35-0.45% carbon; 9.25-11% chromium; 0.8- 2% silicon; 0-1% manganese; v0.5-4.5% molybdenum; 0-3% tungsten and 0-1% each of a member of the group consisting of nickel, cobalt, copper, niobium, tantalum, titanium, vanadium, zirconium, boron and beryllium, the total of said members being a maximum of 1%; and the remainder substantially all iron; the carbon content, and the sum of the chromium content, one-half of the molybdenum content, and one quarter of the tungsten content of said steel falling within the area A-BCDEFA in the accompanying figure.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
US64087A 1966-09-22 1970-07-27 Corrosion-resistant razor blades Expired - Lifetime US3672877A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE1273766 1966-09-22

Publications (1)

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US3672877A true US3672877A (en) 1972-06-27

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ID=20296227

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US64087A Expired - Lifetime US3672877A (en) 1966-09-22 1970-07-27 Corrosion-resistant razor blades

Country Status (5)

Country Link
US (1) US3672877A (de)
BE (1) BE704112A (de)
DE (1) DE1558649C2 (de)
GB (1) GB1100340A (de)
NL (1) NL6712353A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4180420A (en) * 1977-12-01 1979-12-25 The Gillette Company Razor blades
EP4026926A4 (de) * 2019-09-06 2023-09-27 Proterial, Ltd. Stahl für messer, stahl für martensitische messer, messer und herstellungsverfahren für stahl für martensitische messer

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT159794B (de) * 1937-04-30 1940-11-11 Sandvikens Jernverks Ab Legierter Stahl.
GB801463A (en) * 1954-08-11 1958-09-17 Steirische Gussstahlwerke Process for annealing steel in a vacuum

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4180420A (en) * 1977-12-01 1979-12-25 The Gillette Company Razor blades
EP4026926A4 (de) * 2019-09-06 2023-09-27 Proterial, Ltd. Stahl für messer, stahl für martensitische messer, messer und herstellungsverfahren für stahl für martensitische messer

Also Published As

Publication number Publication date
DE1558649B2 (de) 1971-07-15
BE704112A (de) 1968-02-01
GB1100340A (en) 1968-01-24
DE1558649C2 (de) 1975-11-20
DE1558649A1 (de) 1971-07-15
NL6712353A (de) 1968-03-25

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Owner name: SANTRADE LTD., ALPENQUAI 12, CH-6002, LUCERNE, SWI

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SANDVIK AKTIEBOLAG, A CORP. OF SWEDEN;REEL/FRAME:004085/0132

Effective date: 19820908