440C, corrosion resistant cold work, plastic mold steel, good machinability, excellent polishing properties, low distortion, high hardness and wear resistance.
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Imperial and Metric Steel Sizes for Sale
Imperial Steel Size
440C Stainless Steel Standard values
Working hardness:
57 HRC - 60 HRC
Delivery condition:
max. 285HB
Chemical composition in %
0.950000
0.951.200000
1.20.000000
01.000000
10.000000
01.000000
10.000000
00.040000
0.040.000000
00.015000
0.01516.000000
1618.000000
180.400000
0.40.800000
0.8440C Stainless Steel Technical Data
440C Stainless Steel Technical Properties
Stainless, martensitic steel with high hardness and high wear resistance and good cutting power due to the higher carbon content. Compared to the AISI 440B this steel has a slightly higher hardenability at the expense of the corrosion resistance. The material is conditionally acid resistant.
440C Stainless Steel Applications
knives for the food industry, frozen food cutters, pork and beef cleaving knives, fish industry knives, accessories for meat grinders
440C General Information
440 stainless steel, a high martensitic stainless steel, has high strength, good hardness, wear resistance and moderate corrosion resistance. After the correct heat treatment, 440C has the capability to reach the highest strength, hardness and wear resistance among the corrosion and heat resistant stainless steels. Corrosion resistance is lower than for the usual austenitic grades, and their useful operating temperature range is limited by loss of ductility at temperatures below zero and loss of strength due to over-tempering at higher temperatures as well as the reduction in corrosion resistance. In both its pre-hardened and post-hardened condition 440C is magnetic.
Applications
Applications for this stainless steel include: ball bearings, bushings, valve parts, cutlery, knives and blades, nozzles, pump parts.
Corrosion resistance
440C stainless steel has good resistance to atmosphere, fresh water, fruit and vegetable juices, alkalis and mild acids and its corrosion resistance is similar in many environments to 304 stainless steel. Achieve maximum corrosion resistance by hardening from 2000°F (1093°C), to provide a better carbide solution, meaning the better the finish of the hardened and tempered part, the better its corrosion resistance. A smooth polished surface will support this as well. Care should be taken, however, to minimize the time at 2000°F (1093°C) to avoid excessive coarsening of the grain. For optimum corrosion resistance, the tempering temperature should be below 800°F (427°C).
Heat resistance
The use at temperatures above the respective tempering temperature is not recommended, as mechanical properties will deteriorate due to over-hardening.
Heat treatment
440C is a martensitic stainless steel, thus it is hardenable by heat treatment. To achieve the creation of martensite, it is necessary to reduce the amount of austenite by heat treatment.
Annealing
Full anneal at 1562-1652°F (850-900°C), then slowly cool in the furnace to about 1112°F (600°C) and then cool further in air to room temperature.
Sub-critical anneal at 1355-1445°F (735-785°C), then slowly cool to room temperature in the furnace.
Hardening
Heat to 1850-1950°F (1010-1066°C), followed by quenching in warm oil or cooling in air. Oil quenching is necessary for large sections or complex parts. Be aware not to overheat, as full hardness cannot be reached and temper immediately to achieve a wide range of hardness values.
Tempering
440C is tempered at a temperature range of 302-698°F (150-370°C) where several levels of hardness and mechanical properties can be obtained. Tempering in the range of 797-1049°F (425-565°C) reduces impact strength and corrosion resistance and should be avoided.
For our tempering diagram, please click here
Sub-zero Treatment
Quenching 440C down to cryogenic temperatures reduces the austenite content of the steel. Before the tempering process, 440C can be treated either by deep or shallow cryogenic treatment.
To increase hardness up to 7% with the deep cryogenic treatment cool the steel to -321°F (-196°C) and hold at this temperature for 24 hours, then bring back to room temperature.
To increase hardness up to 4% with the shallow cryogenic treatment cool the steel to -112°F (-80°C) and hold for 5 hours and bring the temperature back to room temperature.
The steel then can be tempered at 392°F (200°C) after the cryogenic treatment.
Machinability
Machining, such as turning or drilling, is mostly done in the annealed condition. As a result to its high carbon content it machines similar to high speed steel. Chip curlers and breakers should be used as chips are tough and stringy.
Heat treated 440C is more difficult and probably impossible to machine due to its high hardness.
Welding
As 440C has high-hardness capabilities, and it can air harden easily, this alloy is not welded often. Though if welding is necessary, preheat and maintain at 500°F (260°C). Immediately after the parts need a 6-8 hour anneal at 1350-1400°F (732-760°C) with a slow furnace cool. Do not allow to cool below 500°F (260°C) between welding and annealing. Use high welding inputs and consider a similar filler metal to achieve complementary mechanical properties.
Resistance to scaling (oxidation)
At about 1400°F (760°C) 440C stainless steel scales. With the type of atmosphere, construction and cycle of operation, this temperature will vary.
Grinding and Polishing
For cutlery applications, grinding and polishing is very important. Loss of hardness and corrosion resistance can occur when overheating.
Disclaimer
The data shown here has been compiled with the greatest diligence and is regularly updated with regard to the correctness and completeness of its content. The content is indicative only and should not be taken as a warranty of specific properties of the product described or a warranty of suitability for a particular purpose. All information presented is given in good faith and no liability will be accepted for actions taken by third parties in reliance on this information. ABRAMS Industries reserves the right to change or amend the information given here in full or parts without prior notice.