Overview:

440C Stainless steel is a type of modern steel and famous for it’s 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 good resistance to the atmosphere, fresh water and mild acids. It has best resistance in the hardened, tempered and passivated condition. It allows creating a smooth polished surface and Razor sharp edges. It is being used in cutting instruments, rolling element bearings, valve seats, high quality knife blades, surgical instruments, chisels, ball bearings and valve parts and most commonly used in the production of Cutting tools, including Haircutting Scissors, daggers and swords.

Grades 440A and 440B are identical except for slightly lower carbon contents (0.60 - 0.75% and 0.75 - 0.95% respectively), they attain lower hardness but slightly higher corrosion resistances. Although all three versions of this grade are standard grades, in practice 440C is more available than the A or B variants.

Another alloy 440F (UNS S44020) also exists, with the same high carbon content as 440C.

Heat Resistance:

Not recommended for use in temperatures above the relevant tempering temperature, because of reduction in mechanical properties by over-tempering.

Heat Treatment:

Annealing - Full anneal - 850-900°C, slow furnace cool to about 600°C and then air cool. Sub-critical Annealing - 735-785°C and slow furnace cool. 

Hardening - Heat to 1010-1065°C, followed by quenching in warm oil or air. Oil quenching is necessary for heavy sections. Immediately temper at 150-370°C to obtain a wide variety of hardness values and mechanical properties as indicated in the accompanying table.

Tempering in the range 425-565°C is to be avoided because of reduced impact resistance and corrosion resistance. Tempering in the range 590-675°C results in lower hardness (the product become machinable) and high impact resistance.

Welding

If welding is necessary pre-heat at 250°C and follow welding with a full anneal. Grade 420 filler will give a high hardness weld (not as high as the 440C). Generally welding of 440C is not recommended due to its hardening capability which can lead to the formation cracks within or near the weld.

Machining

In the annealed condition this grade is relatively easily machined; approximately the same as for high speed steel. If this grade is hardened machining becomes very difficult and probably impossible.

440C Composition

Composition ranges for 440 grade stainless steels.

440C Physical Properties

Physical properties for grade 440 stainless steels.

440C Related Specifications

440C Scissors

All scissors shown in our web catalogue are available in 440C Stainless steel. Please choose your scissors' design and send your inquiry now.