US3499803A - Method of treating stainless steel - Google Patents

Method of treating stainless steel Download PDF

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Publication number
US3499803A
US3499803A US615441A US3499803DA US3499803A US 3499803 A US3499803 A US 3499803A US 615441 A US615441 A US 615441A US 3499803D A US3499803D A US 3499803DA US 3499803 A US3499803 A US 3499803A
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Prior art keywords
carbon
stainless steel
steel
carbon content
stainless
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US615441A
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English (en)
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John A Henrickson
Nicholas Makrides
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United States Steel Corp
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United States Steel Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
    • B32B15/011—Layered products comprising a layer of metal all layers being exclusively metallic all layers being formed of iron alloys or steels
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S148/00—Metal treatment
    • Y10S148/902—Metal treatment having portions of differing metallurgical properties or characteristics
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4981—Utilizing transitory attached element or associated separate material
    • Y10T29/49812—Temporary protective coating, impregnation, or cast layer

Definitions

  • This invention relates to a method for producing high carbon stainless steel products which are useful for producing razor blades and cutlery.
  • the product produced is characterized by the absence of large primary carbides which renders it particularly suitable for use as cutting edges.
  • Stainless steels have recently been used for the production of a significant portion of the razor blades marketed.
  • the usual stainless steels which have been used for this purpose contain nominally 0.95% carbon, 0.9% manganese, 0.02% phosphorus, 0.02% sulfur, 0.25% silicon and 13.5% chromium.
  • Razor blades, for example, of this composition may be used much longer than high-carbon, lowalloy steels formerly employed for this purpose.
  • stainless steels are superior to the carbon steels formerly used, a number of problems exist in razor blade production of stainless steel blades not only for the steelmaker but for the razor blade manufacturer as well.
  • One major problem in the manufacture of razor blades is the presence of large carbides which may form during the solidifcation of molten stainless steel.
  • the present method avoids the aforementioned difficulties. It is applied to non-austenitic, stainless steels, that is, to ferritic or martensitic stainless steels, having a carbon content below that at which massive carbides will form. Austenitic stainless steels would not be used because of their inability to harden to required levels.
  • the invention involves increasing the carbon content of the martensitic or ferritic stainless steel to the amount required to provide the desired hardness for such applications as razor blades by diffusing carbon into the stainless steel.
  • the carbon content of the stainless steel may be provided in the desired range of 0.7 to 1.3% which is required for many cutlery applications.
  • the preferred carbon content is, however, about 0.8 to 1% while 0.9% is preferred for razor blade production.
  • Increasing the carbon content may be achieved by diffusion wherein the stainless steel is subjected at elevated temperatures to one of three carbon diffusion treatments. These treatments are:
  • gases which may be used include carbon monoxide, methane and ethane.
  • gases which may be used include carbon monoxide, methane and ethane.
  • the composite structure in the form of hot or cold-rolled strip material is heated in an atmosphere of the aforementioned gases at temperatures within the range of about 1400 to 1900D F. for a time sufficient to develop the desired carbon content in the carbon steel portion of the composite, which usually takes between l to 24 hours.
  • a second method of carbon diffusion concerns the use of a carbon-containing liquid.
  • Liquid baths of sodium cyanide, barium chloride and sodium carbonate may be used for this purpose.
  • the required heating times and temperatures are the same as those used in gaseous diffusion.
  • the third method of carbon diffusion to increase the carbon level of ferritic or martensitic stainless steel is by the use of a carbon-containing solid.
  • carbon steel having at least about 0.7% carbon is used.
  • steel with a lower carbon content, but at least about 0.05% carbon may be used if carburized to at least about 0.7% carbon.
  • Carbon diffusion can also be attained by intimate contact of the composite strip surface with solid carbon particles to carbonize the clad portion of the composite.
  • the clad jacket in this case would be a low-carbon steel to facilitate initial processing. The subsequent treatment to obtain diffusion of the carbon to the stainless steel core would not change but the point in processing at which it may be applied can vary.
  • Example of a preferred embodiment which involves carbon diffusion by use of a solid, carbon-containing material in accordance with the invention is as follows:
  • One carbon strip was spot welded to each face of the stainless steel insert.
  • the composites were held at the latter temperture for four hours and then cooled to 1100 F. and finally air cooled to room temperature.
  • the carbon content of the stainless steel insert after this treatment increased from 0.15 to 1.10% carbon.
  • stainless steel with this carbon content developed a minimum hardness of 65 RC which is the specification requirement for stainless steel razor blade cutting edges.
  • a heat treatment at 1600" F. will increase the carbon level above the 0.70% minimum normally desired and will also spheroidize the carbides present. Thus, in diffusing at about this temperature, the primary carbides that heretofore caused tear outs do not develop.
  • FIG- URES 1 and 2 A comparison of the metallurgical structure showing the presence of large primary carbides with conventionally produced stainless steel specimens and tl'ie product produced in accordance with the invention appear in FIG- URES 1 and 2, respectively.
  • FIGURE 1 is a photomicrograph of a conventional stainless razor blade steel annealed at 1650 F., etched with HCl-picric etchant and at 1000 showing large primary carbides.
  • the photomicrograph in FIGURE 2 is of a carburized steel core of stainless razor blade steel austenitized at 1950 F., quenched in water, requenched at 100 F. and ternpered at 400 F., treated with the same etchant and at the same magnification.
  • the product produced in accordance with the invention contains only small secondary carbides which is not the case with stainless steel shown in FIGURE 1. Moreover, the structure shown in FIGURE 2 developed a hardness on the order of 65 RC after the hardening and tempering treatment described and thus meets the requirement for stainless steel razor blade cutting edges.
  • the assembly was cold rolled from about 0.09-inch thick strip to 0.0l-inch thick razor blade strip using four anneals with total reductions of about 40% between each anneal.
  • the annealing cycles were conducted at 1300 F.
  • the carbon content of the carbon steel after diffusion is reduced from about 1.25% to about 0.20%.
  • This steel core can be used in the manufacture of a clad stainless Steel razor blade or in the production of an all stainless razor blade by pickling or scaling to remove the carbon steel jacket.
  • the steel cladding after hot rolling to bond the core and cladding, is carburized in any suitable or conventional manner to raise the carbon content of the cladding steel to at least about 0.7%.
  • the carburizing treatment described above in connection with gaseous diifusion may be used here.
  • the elimination of primary carbides by practicing the present invention minimizes or eliminates the occurrence of tear outs during the grinding of blade cutting edges.
  • this improves the life of the blade-slitting and perforating dies and increases the steel hardening rates by virtue of the faster solution rate of fine carbide compared with that of larger carbides.
  • a method of treating stainless steel to produce a product which is characterized by the absence of large primary carbides and is useful for manufacturing cutlery, and wherein the carbon content of the ultimate stainless product is greater than the initial carbon content of the stainless steel comprises assembling a sandwich of a non-austenitic stainless steel core within carbon steel claddings, the carbon content of said stainless steel being initially less than about 0.6% and the carbon content of said carbon steel being initially at least about 0.7%, hot rolling said sandwich to metallurgically bond the core and claddings into a composite, and holding the hot-rolled composite at about 1400 to 1650o F. to diffuse carbon from said carbon steel into the stainless steel core so as to increase the carbon content thereof to above about 0.7% and lower the carbon content of said claddings to about 0.2%.
  • a method of treating steel comprising assembling a sandwich of a non-austenitic stainless steel core within carbon steel claddings, the carbon content of said stainless ysteel being initially less than about 0.6% and the carbon content of said carbon steel being initially at least about 0.05 hot rolling said sandwich to metallurgically bond the core and claddings into a composite, carburizing the composite to raise the carbon content of said carbon steel to at least 0.7%, and holding the hot-rolled composite at about 1400 to 1650L7 F. to diffuse carbon from said carbon steel into the stainless steel core so as to increase the carbon content thereof to above about 0.7% and lower the carbon content of said cladding to about 0.2%.

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  • Heat Treatment Of Sheet Steel (AREA)
US615441A 1967-02-13 1967-02-13 Method of treating stainless steel Expired - Lifetime US3499803A (en)

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US61544167A 1967-02-13 1967-02-13

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BE (1) BE710404A (it)
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3693240A (en) * 1969-08-27 1972-09-26 Sandvikens Jernverks Ab Method of manufacturing filler material for welding
US3775194A (en) * 1970-12-21 1973-11-27 Texas Instruments Inc Composite material, tubing made from the material, and methods for making the material and tubing
US3867212A (en) * 1972-03-16 1975-02-18 Texas Instruments Inc Composite material, tubing made from the material, and methods for making the material and tubing
US3891820A (en) * 1971-08-25 1975-06-24 Siemens Ag Weld-plating of steel
US4035204A (en) * 1974-10-30 1977-07-12 Robert Bosch G.M.B.H. Method of carburizing the inner surface of a steel valve seat
US20070277492A1 (en) * 2006-05-31 2007-12-06 Imants Ekis Self-sharpening disc mower blade

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3339904A1 (de) * 1983-11-04 1985-05-15 Bergische Stahl-Industrie Dreischichtstahl und seine verwendung fuer kuttermesser etc.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2531731A (en) * 1946-11-29 1950-11-28 Carnegie Illinois Steel Corp Razor blade stock
US3116180A (en) * 1957-04-27 1963-12-31 Neuzeughammer Ambosswerk Messe Method of producing articles having a cutting edge portion and consisting of stainless chromium steel
US3313660A (en) * 1963-07-15 1967-04-11 Crucible Steel Co America Cutting articles and stock therefor and methods of making the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2531731A (en) * 1946-11-29 1950-11-28 Carnegie Illinois Steel Corp Razor blade stock
US3116180A (en) * 1957-04-27 1963-12-31 Neuzeughammer Ambosswerk Messe Method of producing articles having a cutting edge portion and consisting of stainless chromium steel
US3313660A (en) * 1963-07-15 1967-04-11 Crucible Steel Co America Cutting articles and stock therefor and methods of making the same

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3693240A (en) * 1969-08-27 1972-09-26 Sandvikens Jernverks Ab Method of manufacturing filler material for welding
US3775194A (en) * 1970-12-21 1973-11-27 Texas Instruments Inc Composite material, tubing made from the material, and methods for making the material and tubing
US3891820A (en) * 1971-08-25 1975-06-24 Siemens Ag Weld-plating of steel
US3867212A (en) * 1972-03-16 1975-02-18 Texas Instruments Inc Composite material, tubing made from the material, and methods for making the material and tubing
US4035204A (en) * 1974-10-30 1977-07-12 Robert Bosch G.M.B.H. Method of carburizing the inner surface of a steel valve seat
US20070277492A1 (en) * 2006-05-31 2007-12-06 Imants Ekis Self-sharpening disc mower blade

Also Published As

Publication number Publication date
FR1554305A (it) 1969-01-17
BE710404A (it) 1968-08-06

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