S. S. 440A / 440B / 440C

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UNS - S44002 / S44003 / S44004

Grade 440A is a high-carbon martensitic stainless steel created to give stainless properties with maximum hardness. It is magnetic in both the annealed as well as hardened conditions. Maximum hardness and corrosion resistance are accessible only in the hardened or hardened and stress relieved conditions, so the alloy is not utilized in the annealed or annealed and tempered conditions. Grade 440B stainless steel is a high carbon martensitic stainless steel consisting good strength, moderate corrosion resistance and capacity to get and keep up wear resistance and magnificent resistance.

Grade 440C Stainless Steels are high carbon steels, which achieve the most elevated hardness, wear resistance and strength of all stainless steel grades after heat treatment. These properties make this grade suitable for applications for example, valve components and ball bearings. Grade 440A and 440B stainless steels, on the other hand, have comparable properties - with the exception of slightly lower percentage of carbon in grade 440A. Each of the three types of grade 440 stainless steelsis ordinarily utilized. So, grade 440C is more promptly available than the other standard grades.

Characteristics

• High carbon martensitic stainless with
• Moderate corrosion resistance
• Good Strength
• Ability to obtain and keep excellent hardness and wear resistance

Applications

• Chisels
• Surgical equipment
• High quality knife blades
• Valve seats
• Rolling element bearings

Machining
This utilized best machined in the annealed condition. By utilizing chip breakers tough, stringy chips can be easily handled. Ceramic or carbide tooling is recommended.

Welding

These alloys are not generally welded because of tendency to air harden. If it must be welded, post weld treat at 1350-1400 F (732-760 C) for 6 hours and preheat to 500 F (260 C) followed by a slow furnace cooling to avoid cracking. Use comparable filler metal and high heat inputs during operations.

Hot Working

For 440A grade:
Pre-heat to 1400 F (760 C), then bring slowly up to 1900-2200 F (1038-1204 C)before proceeding. Do not work this material below 1700 F (927 C). Cool material slowly after working and once at room temperature, anneal fully.****Pre-heat to 1400 F (760 C), then bring slowly up to 1900-2200 F (1038-1204 C) before proceeding. Do not work this material below 1700 F (927 C). Cool material slowly after working and once at room temperature, anneal fully.
For 440B & 440C grade:
Pre-heat to 1400 F (760 C), then bring slowly up to 1900-2200 F (1038-1204 C)before proceeding. Do not work this material below 1700 F (927 C). Cool material slowly after working and once at room temperature, anneal fully.

Cold Working

These alloys are treated just slightly cold workable by common practices.

Annealing

Annealing to1550-1600 F (843-871 C) pursued by very slow furnace cooling.

Tempering

For maximum properties, soak at 300 F (148 C). Maximum obtainable hardness is (440A) RC 56, (440B) RC 58 and (440C) RC 60.

Hardening

Bring the material slowly up to 1400 F (760 C), then on to a soak temperature of 1850 F (1010 C), air or oil cool.

Chemical Composition %


Mechanical Properties


Physical Properties


ASTM Specifications


Availability

For 440A grade:



For 440B & 440C grade: