Stainless Chromium Steel For Razor Blades

Stainless chromium steelfor razor blades

Our integrated production, combined with R&D, ensure ongoing product development and our ability to meet customers' individual requirements.Razor blade steelSandvik 13C26For more than eighty years Sandvik Materials Technology hasmanufactured stainless strip steel. The knowledge and experiencewhich we have gained is invested in the active and ongoingdevelopment of our products.With our own metallurgy and strip production, we controlthe whole production chain from steel melt to finished product,using the latest, most reliable technology.Sandvik 13C26 is a martensitic stainlesschromium steel used mainly for razorblades.Forms of supply, finishes anddimensionsRazor blade steel, Sandvik 13C26, is supplied as cold rolled strip in coils. The tensilestrength is 1070 100 MPa (155 14.5 ksi).The strip is supplied with a dull, very finesurface, slit edges and extra accuracy onstraightness. Wide strip is slit into finishedsizes in special slitters with cemented carbidetools, which give very high edge quality andvery close width tolerances. A corrosionpreventive oil is applied to the strip. Coilsare carefully packed, with various packingmaterials being used, according to customerrequirements, destination and method oftransport.Coil sizesRazor blade strip is wound into pancakecoils on plastic cores with an inner diameterof 280 mm (11.0 inches). The coils can besupplied in weights between 1 and 5 kg/mm(55-280 lbs PIW) strip width, which meansan outer diameter from about 500 to 1000mm (20-40 inches).WidthWidths range between 5 and 26 mm(0.2 –1.0 inches).Other dimensions and forms of supply canbe produced to meet specific requirements.GRADECHEMICAL COMPOSITION, NOMINAL, Dimensions and tolerancesSTRIP THICKNESSTHICKNESS TOLERANCEmminchmm inch 0.0760.00300.0050.000200.0990.00390.0050.000202

Pictures from left: Scanning electron microscope (SEM), melting, continuous casting, cold rolling, inspection, slitting, packing and deliver y.MicrostructureUnhardened condition ‘as delivered’In the ‘as delivered’, unhardened condition,Sandvik 13C26 consists of finely dispersedcarbides in a ferritic matrix, see figure 1.tributes significantly to the quality of therazor blade edge. Careful process controlalso ensures that the chemical compositioncan be kept within very close limits, whichresults in consistent steel properties.Hardened and tempered conditionAfter hardening and tempering, Sandvik13C26 consists of a martensitic matrixwith undissolved carbides and some retained austenite, as shown in figure 2. In thiscondition the steel has good corrosionresistance.Figure1. Sandvik 13C26 ‘as delivered’, unhardened.The carbides are of type M23C6, where Mstands for iron and chromium. This typeof carbide is easily dissolved during heattreatment, which is important for goodhardening results.The fine dispersion of thecarbides also helps to speed up their dissolution, allowing lower furnace temperaturesand higher speeds during hardening.The ferritic matrix has low contents ofcarbon and chromium, because these elements are bound in carbides. Since thechromium content in the matrix determines the corrosion resistance of the steel,the material has limited resistance to corrosion in the ‘as delivered’ condition.Because of very careful control in themanufacture of the steel, large carbides –known as primary carbides – can be avoided, and the amount of non-metallic inclusions can be kept to a minimum.This con-Figure 2. Sandvik 13C26 hardened and tempered.Heat treatmentThe recommended heat treatment forSandvik 13C26 follows the temperaturecycle illustrated in figure 3.During heating [1], or austenitising, theferrite is transformed into austenite andthe carbides are partly dissolved. Becauseof the carbide dissolution, the contents ofcarbon and chromium in the matrixincrease. The subsequent quenching toroom temperature [2] will transform mostof the austenite into martensite. Duringdeep freezing of the material to -70 C(-94 F) [3], even more austenite is transformed into martensite. The remainder,about 15 %, is known as retained austenite.Finally, since the material is now very brittle, the toughness, and also the hardness, isincreased by a tempering treatment [4].PropertiesHardnessThe martensite content and the amount ofretained austenite mainly determine thehardness in the hardened and temperedcondition. Martensite becomes harder withincreasing carbon content. The higher theaustenitising temperature, the higher thecontent of carbon in the subsequentlyformed martensite.On the other hand, the more carbon inthe matrix at austenitising, the more austenite will be retained after quenching anddeep freezing. Since austenite is softer thanmartensite, this will reduce the hardness.These two contradictory effects indicatethat for Sandvik 13C26, there is an optimum combination of hardening temperature and time. This heat treatment cycle isshown in figure 3.Corrosion resistanceDue to the dissolution of carbides duringheat treatment, the chromium content ofthe matrix increases. Good corrosion resistance is achieved with a chromium contentof 11–12 %. This is obtained by a heattreatment that leaves about 15 % ofretained austenite after quenching anddeep freezing, see figure 3.3

Te m p e ra t u reSandvik GroupThe Sandvik Group is a global high technologyenterprise with around 300 subsidiary companies, 37,000 employees and activities in morethan 130 countries.Sandvik’s operations are concentrated onits three core businesses of Materials Technology,Tooling and Mining and Construction – areas inwhich the group holds leading global positionsin selected niche markets.Sandvik Materials TechnologyTimeSandvik Materials Technology is a world-leadingsupplier of products with extensive added valuein advanced metals, special alloys, metallic andHV 0.3 kg340–720770780Ferrite, %88––––ceramic resistance materials as well as processCarbides, %125555plants based on steel conveyor belts, andAustenite, %–95251515Martensite, %––708080Figure 3.Temperature cycle for hardening of Sandvik 13C26. [1] 25 seconds above1000 C (1830 F); 10 seconds at top temperature 1080–1100 C (1975–2010 F).All values are approximate and only for guidance.Further informationAdditional technical information can befound in the following brochures/datasheets.S-333-ENGStrip steel for edgeapplicationsS-300-ENGSpecial strip steelS-3822-ENG Sandvik 13C26 knife steelsorting systems.Quality assuranceSandvik Materials Technology has a qualitymanagement system, approved by internationallyrecognised organisations. We hold for example:ASME Quality System Certificate as a MaterialsOrganisation, approval to ISO 9001 as well asapprovals from LRQA, JIS and other organisations as a materials manufacturer.EnvironmentEnvironmental awareness is an integral partof our business and is at the forefront of allactivities within our operation. We hold ISO14001 approval.4

Sandvik 13C26 offersthe following advantages Excellent metallurgical properties Close tolerances Smooth surface, extra accuracyon flatness and straightness Good blanking properties Good hardening properties Good grinding and honing properties,facilitating the manufacture of highquality edges Good corrosion resistance(hardened and tempered condition) Consistent material properties fromcoil to coil, from delivery to delivery

S-3332-ENG. Dec 2002. Pr inted in Sweden: AB Sandvikens Tr ycker i. Ason&Co.AB SANDVIK MATERIALS TECHNOLOGY, SE-811 81 SANDVIKEN, SWEDEN, PHONE 46 26-26 30 00, FAX 46 26-26 02 65e-mail: edgeapplications@sandvik.comw w w. s m t . s a n d v i k . c o m

Sandvik 13C26 is a martensitic stainless chromium steel used mainly for razor blades. Forms of supply, finishes and dimensions Razor blade steel, Sandvik 13C26, is supp-