Martensitic stainless steels ( quoted from ISSF )

In 400 series family, it contains nonhardenable ferritic stainless steels (0.02 to 0.06% carbon, 10.5 to 30% chromium, 

0 to 4% molybdenum. Commonly used internally, these grades are now being developed for envelope and structural products. Applications including Car exhaust systems, conveyor chains, cooking utensils, boilers domestic electrical appliances, domestic appliances, trim, dishware, heating, hot water tanks, tubes.. )

and martensitic stainless steels ( typically contain 12 to 17% chromium and nickel in a range from 0 to 5%. 

The lower nickel content offers the secondary advantage of a lower material cost. Martensitic stainless steels, like 

other stainless steel families, provide a long, low maintenance product life, and it benefits from an excellent recycling rate. )

Martensitic groups

martensitic stainless steels contains more than 10.5% chromium and their mechanical properities can be adjusted by 

heat treatment, just like engineering steels. 

They fall into 4 groups.

1. Fe-Cr-C steels, they are the first grades put into use and still widely used in engineering and in wear resistant applications.

2. Ni-bearing grades, in which Ni replaces some of the C, compared to the previous group, they offer a higher 

toughness particularly at low temperatures. 

Their higher Cr content leads to a higher corrosion resistance. 

Mo additions in groups 1 and 2 improve further the corrosion resistance.

3. Precipitation hardening stainless steels, offer the best combination of strength and toughness.

4. Creep resisting grades, with about 11% Cr, differe from group 1 by addition of Co, Nb, V and B which increases of

 high temperature strength and creep resistance up to 650℃.

Martensitic stainless' special characteristics:

1. high mechanical properities

2. high hardness and wear resistance

3. good creep resistance of the Co/V/Nb/W/B grades

4. higher stiffness

5. moderate to good corrosion resistance

6. magnetic

7. thermal conductivity

8. thermal expansion coefficient

9. improved machinability grades

Some applications:

Automotive

• martensitic stainless steels are used in a wide variety of applications, which have in common:
• high temperature properities
• corrosion resistance to gasoline or to outside environment
• critical parts

These include:

• shafts of electric motos ( 1.4021, 1.4034, 1.4029 stainless )
• injection pump components ( 1.4418 stainless )
• common rail parts ( 1.4057, 1.4418 stainless )
• sensors ( 1.4542 stainless )
• intake valves ( 1.4718 stainless )
• high temperature bolts ( 1.4923 stainless )

Oil and gas

oil drilling, mud motors, manufactured from EN 1.4542, AISI 630, 17-4PH precipitation hardening stainless steel.

Oil production

martensitic stainless steels are suitable for sweet ( CO2) environments, under which standard carbon and low alloy 

steels would suffer localized corrosion also called mesa or ringworm corrosion. 

While 13Cr% ( Type EN 1.4016, DIN X12Cr13, AISI 410 ) was almost the only martensitic grade used years ago, 

now new martensitic grades, usually referred to a super martensitic S13Cr and S17Cr are increasingly used as they 

bridge the gap of performance between 13Cr and Duplex materials by providing a larger application domin with regards 

to temperatures, H2S content and chloride concentration. 

Aerospace

high strength martensitic stainless steels and particularly grades EN 1.4542, AISI 630 are commonly used in aerospace,

 in a wide variety of applications, of which hydraulic systems, landing gear, shafts, actuators, fasteners..

Mechanical engineering

pump bodies, impellers and shafts, valve bodies, stems etc.. pipe fittings, extruders in the food industry, bolts, 

conveyor systems...

Cutlery and cutting tools

well known uses of stainless martensitic steels, typical grades EN 1.4021, DIN X20Cr13, AISI 420A, EN 1.4028, 

DIN X30Cr13, AISI 420B,  EN 1.4031, DIN X39Cr13, AISI 420X, EN 1.4034, DIN X46Cr13, AISI 420C, EN 1.4122, 

DIN X39CrMo17-1, EN 1.4116, DIN X50CrMoV15, EN 1.4037, DIN X65Cr13, EN 1.4109, DIN X70CrMo15,

AISI 440A, EN 1.4125, DIN X105CrMo17, AISI 440C

Brake discs, stainless steel grade AISI 420

Moulds for glass bottles

stainless steel grade EN 1.4057, DIN X17CrNi16-2, AISI 431, DIN 1.2787

Moulds for plastic injection

AISI 420, EN 1.4031, DIN X39Cr13 or EN 1.4122, DIN X35CrMo17