Stainless Steel SS 440c / S44004 /

Transcription

1 Stainless Steel SS 440c / S44004 / Characteristics This material will achieve the highest hardness of the available hardenable stainless steels. It possesses good corrosion resistance, particularly in the hardened and tempered condition. The material is magnetic in all conditions. Corresponding Standards: DIN AFNOR - Z100CD17 UNI - X102CRMO17KU AISI - 440C UNS - S44004 EN - X105CrMo17C Availability : Alloy 440C is available as round / flat. Chemical Composition Chemical composition (%) C Si Mn P S Cr Mo 0,95-1,20 1,00 1,00 0,040 0,030 16,00-18,00 0,75 Stocking Diameters Material Lengths ½ to 16 Up to 12 Bar Specifications Uns Type Ams Astm Federal Characteristics S C A-276 A-314 A-493 QQ-S A, B, and C all have the same basic composition with varying high carbon contents. This produces higher strength/hardness with 440 versions. Corrosion resistant only in the hardened condition. Technical data: Hot forming temperature C Annealing temperature C Hardening temperature C Quenchant Oil Tempering temperature C

2 Structure after Heat treatment Condition Product Size mm Hardness (average values) HB/HV Ferrite + Carbide max. 285 Martensite + Carbide Martensite + Carbide hardened & tempered for obtaining high hardness ca. 61 HRC HRC Physical properties at ambient temperature (average values): Modulus of elasticity 103 N/mm2, at... C Density kg/dm3 Electric resistivity Ohm.mm2/m Thermal conductivity W/(m.K) 20 C 100 C 200 C 300 C 400 C ,70 0,80 15 Physical properties: Specific heat capacity at 20 C Mean coefficient of thermal expansion between 20 C and... C, 10 (m/(m.k) 100 C 200 C 300 C 400 C 500 C Magnetic properties 430 J/ (kg.k) 10,4 10,8 11,2 11,6 11,9 Magnetic Heat Treatment Practice In order to achieve the optimum properties for this material, it is imperative that the correct heat treatment is carried out in accordance with the following recommendations Annealing Annealing may be required on material in the as forged condition in order to aid machining prior to hardening and tempering. Annealing should be carried out under vacuum conditions to avoid surface decarburisation. Annealing: Process anneal 675ºC - 760ºC Full anneal 845ºC - 900ºC Hardness achievable: 23/25 HRc Note: The material supplied by Intoco is already in the annealed condition unless otherwise stated. Normalising Normalising is not recommended Hardening Hardening should be carried out under vacuum conditions to avoid surface decarburisation and to maintain a clean bright product. Preheat 760ºC - 800ºC Austenitise 1010ºC ºC Nitrogen gas quench 2-6 bar overpressure As quenched hardness 60/62 HRc

3 The upper end of the temperature range should be used for larger sections or when maximum corrosion resistance and strength are required. Similarly the greater quench pressure should be used in order to maximize these properties. Sub Zero treatment For minimum retained austinite and maximum dimensional stability, parts should be sub-zero treated between -70º / -80ºC. This should be carried out immediately after hardening once the parts have reached ambient temperature. Tempering Tempering should be carried out depending on properties required, in all cases double tempering is recommended. 165ºC for maximum hardness 60 HRc 190ºC - 230ºC for a combination of hardness & toughness 56/58 HRc 350ºC for maximum toughness 52/54 Hr Industries that use 440C include: Machine shop Tool Utensils Products partially or completely constructed of 440C include: Ball bearings Knives Mold inserts Nozzles Surgical tools Valves Wear parts of pumps Applications Grade 440C stainless steel is used in the following applications: Gage blocks Cutlery Ball bearings and races Molds and dies Knives Valve components Measuring instruments 440-C stainless steel was originally used in bearing assembles, including ball bearings and races. It is widely used in cutlery, valve seats, needle valves, ball valves, pump parts, bushings and textile machinery. Additional Technical Information for / 440c: Grades 440A and 440B are the same excluding for faintly worse carbon contents ( % and % respectively), they attain lower hardness but slightly higher corrosion resistances. Although the entire three versions of this grade are standard grades, in practice 440C is more offered than the A or B variants. Another alloy 440F (UNS S44020) also exists, with the same high carbon content as 440C. 440C Stainless steel is a form of recent steel and well-known for its high corrosion resistant, wear resistance, strength and hardness qualities among all the stainless alloys, capable of attaining (after heat treatment) the highest hardness (60 HRC). It has excellent resistance to the environment, fresh water and mild acids. It has greatest resistance in the hardened, tempered and passivated condition. It allows creating a soft polished surface and Razor sharp edges. It is being used in cutting tools, rolling factor bearings, valve seats, high value knife blades, surgical instruments, chisels, ball bearings and valve parts and most normally utilized in the production of Cutting tools, including Hair-cutting Scissors, daggers and swords. Not suggested for utilize in temperatures above the significant tempering temperature, because of diminution in mechanical properties by over-tempering. Annealing - Full anneal C, unhurried boiler cool to about 600C and then air cool. Subcritical Annealing C and unhurried boiler cool. Hardening - Heat to C, followed by quenching in temperate oil or air. Oil quenching is compulsory for serious sectors. Instantly temper at C to obtain a broad diversity of solidity principles and mechanical properties as indicated in the accompanying table. The freezing time depends on the diameter of the workpiece, but for a knife of up to, say, 10 mm thickness (ohhh, Metric system again!!!), in a quenching medium with direct contact (liquid, no gas!) about 20 to 30 minutes are fully sufficient. Performance gain through cryo quench doesn't necessarily mean more HRc points. What you really want is the finer grain you

4 get. This means tougher steel with finer edge and higher abrasion resistance. Hence better sharpness, longer edge holding and easier sharpening. Tempering in the series C is to be avoided because of reduced impact resistance and corrosion resistance. Tempering in the range C results in lower hardness (the product become machinable) and high impact resistance. Mechanical Properties above ambient temperature: Condition: Hardened & Tempered Coefficient of Thermal Expansion between 20ºC and Temperature ºC Coefficient (10-6 K-1) Welding If welding is required pre-heat at 250C and pursue welding with a full anneal. Grade 420 stuffing will provide a high hardness weld (not as high as the 440C). Normally welding of 440C is not suggested due to its hardening ability which can lead to the formation cracks within or near the weld. Machining In the annealed situation this evaluation is relatively easily machined; approximately the same as for high speed steel. If this grade is hardened machining becomes very complicated and almost certainly impracticable. Grade 440C is proficient of attaining, after heat treatment, the highest power, hardness and wear resistance of all the stainless alloys. It's extremely towering carbon substance is responsible for these characteristics, which make 440C mainly suitable to such applications as ball bearings and valve parts. Grades 440A and 440B are like except for vaguely lower carbon contents ( % and % respectively); these have lower attainable hardnesses but slightly higher corrosion resistances. Although all three editions of this grade are standard grades, in practice 440C is more offered than the A or B variants. A free-machining variant 440F (UNS S44020) also exists, with the same high carbon content as 440C. Again this grade is not eagerly presented in Australia. Martensitic stainless steels are optimized for high hardness, and other properties are to some degree cooperations. Fabrication must be by methods that allow for unfortunate weldability and frequently also allow for a final harden and temper heat treatment. Corrosion resistance is lower than the general austenitic grades, and their helpful operating temperature range is limited by their loss of ductility at sub-zero temperatures and loss of power by over-tempering at elevated temperatures. Key Properties These properties are precise for bar product in ASTM A276. Similar but not unavoidably identical properties are specified for other products such as plate and forgings in their respective specifications. In the highly aggressive world of manufacturing, sourcing high quality materials is important. SAGAR STEEL CENTRE industrialized company, specialize in 'no-compromise' SUPPLYING using state of the art CNC apparatus. We are also the INDIA'S largest self-governing stockholder of hot work tool steels. From the understanding gained in buying high superiority tool steel, SAGAR STEEL'S have additional a further steel to their range, this being a Chromium martensitic steel called 440C/1.4125/4125 Stainless Steel. Martensitic stainless steels are optimized for high hardness. The properties are precise for bar product in ASTM A276. It has fine resistance to the environment, fresh water, foods, alkalies and acids. The oxidization resistance of grade 440C/1.4125/4125 approximately matches that of grade 304 in many surroundings. 440C/1.4125/4125 Stainless Steel is used in a broad variety of industries including bearing produce, food applications, aerospace applications, surgical tools, cutlery, etc. Type 440C Stainless Steel is broadly utilized in antifriction bearings, in valves and in a lot of other applications where high hardness and reasonable oxidization resistance is compulsory. This material is much more unwilling to abrasion and wear than chrome steel. It is a elevated alloy, fine grain, through hardening, Martensitic stainless steel. Because of its high hardness and fine grain structure, it can be completed to a fine dimensional quality. 440C is a sky-scraping carbon chromium stainless steel providing stainless steel properties with best hardness after heat

5 action. 440C can reach a hardness of up to 60 Rockwell HRc. 440C stainless resists oxidization in usual domestic surroundings and very gentle industrial environments, with optimum corrosion resistance of 440C achieved with a temper below about 400 C. For 440C to achieve most excellent corrosion resistance, surfaces must be free of range, lubricants, foreign particles, and coatings useful for drawing and heading. With it's high carbon content 440C annealed stainless machines alike to a high speed steel annealed grade Type 440C Stainless Steel is broadly utilized in antifriction bearings, in valves and in a lot of other applications where high hardness and reasonable oxidization resistance is compulsory. This material is much more unwilling to abrasion and wear than chrome steel. It is a elevated alloy, fine grain, through hardening, Martensitic stainless steel. Because of its high hardness and fine grain structure, it can be completed to a fine dimensional quality.