Martensitic stainless steels These grades present similar chemical composition than ferritic grades.
Their higher carbon and lower chromium concentration permit hardening by heat treatment.
Martensitic stainless steels are iron-chromium alloys that contain from 10% to 18% chromium and can be hardened by heat treatment to high strength levels.
Type 410 stainless steel is the basic alloy in this grouping.
The martensitic types are the lowest in their ability to withstand corrosion. Adding more carbon to the basic martensitic alloy increases hardness. But, as carbon is increased, chromium content is also increased to as high as 18% to maintain no less than 10% free chromium for corrosion resistance. Other modified martensitic alloys contain additional elements, such as sulfur or selenium. Martensitic varieties find major applications in products that must resist atmospheric oxidation, mildly corrosive chemicals,
and wet or dry corrosion environments found in steam and gas turbine parts, bearings, and cutlery.
The martensitic types are magnetic in all conditions.
Martensitic Summary: • Hardenable by heat treatment • Magnetic • High strength • Moderate resistance to corrosion • Contains no nickel
Martensitic family tree
410 Base Grade → 416 Increased Sulfur for Higher Machining → 431 Increased Chromium for Higher Corrosion Resistance
420 Add Carbon for Hardness & Strength
GRADE 416 416 is a martensitic chromium steel to which elements have been added to enhance the machinability.
416 is the most readily machinable of all the stainless steels and is suitable for use in automatic screw machines. 416 is less corrosion resistant than the chrome-nickel steels. It is magnetic in all conditions. TYPICAL APPLICATIONS Aircraft fittings, bolts, nuts, studs, rivets, screws, many nonseizing and nongalling applications.
GRADE 410 410 is a martensitic stainless steel that is air or oil hardened and responds well to hardening and tempering operations.
Considered a 12% chromium steel, it offers super combinations of strength and toughness depending on degree of heat treatments.
In the annealed condition, it is a ready choice for forming and cold heading. TYPICAL APPLICATIONS Machined parts, pump shafts, bushings, mining machinery, screws, valves, cutlery, oil burner parts and hardware.
GRADE 420 420 is a martensitic chrome steel capable of hardening to a maximum of approximately 500 Brinell.
It has its optimum corrosion resisting qualities in the hardened and tempered condition.
420 is magnetic in all conditions. TYPICAL APPLICATIONS Flatware knife blades, glass molds, hand tools, vegetable choppers
GRADE 440C 440C is a martensitic chrome steel that is capable of acquiring, upon heat treatment, the highest hardness of any type
of corrosion resisting steels. It has its optimum corrosion resisting qualities in the hardened and tempered condition
and is magnetic in all conditions. TYPICAL APPLICATIONS Instrument bearings, nozzles, steel balls and seats for oil well pumps, valve parts