Martensitic Stainless Steel Alloys Demystified – Properties & Application

Stainless steel, a remarkable alloy born from the marriage of iron and chromium, defies rust and corrosion. Its versatility spans from gleaming kitchenware to towering skyscrapers. Architects adore its sleek appearance, while engineers rely on its strength. Whether in surgical instruments or spacecraft, stainless steel stands as a testament to human ingenuity — a marvel that graces our lives subtly yet profoundly. The crystalline structure of stainless steel divides them into four major types i.e.

• Martensitic
• Austentic
• Duplex, and
• Ferrite.

What is Martensitic Stainless Steel?

Martensitic stainless steel is a type of stainless steel alloy tempered and hardened through various ways of heat or aging treatment. These steels can be very high-carbon or low-carbon steels with the material composition in the following fashion:

• 12% iron
• 17% chromium
• 0.10% Carbon in Type 410.
• 1.2% Carbon in Type 440C.

Use of Martensitic Steel with 0.4% C:

At this composition, Martensitic steel is used in the manufacturing of shafts, valves, and pumps.

Use of Martensitic Steel above 0.4% C:

Martensitic steel having a carbon composition above 0.4% is used to manufacture wear-resistant products, e.g., plastic injection molds, nozzles, and cutlery surgical blades).

Learn about S42000 Martensitic Steel Grade here.

Composition of Different Types of Martensitic Steel Types:

Type 431: It has a higher content of Chromium and Molybdenum content with lower Carbon content. This improves its toughness and corrosion resistance properties.

CA6NM (Grade EN 1.4313): It has 4% Nickle and 13% Chromium with low Carbon content. This composition gets good weldability, castability, mechanical properties, and good resistance against cavitation. The primary use of this Martenstitic steel grade is in hydroelectric turbines.

Adding Beryllium, Titanium, Nickel, and Cobalt in Martensitic steel improve its high-temperature properties, especially creep resistance.

Chemical Compositions of Various Martensitic Steel Grades:

EN Number	Carbon Composition in %	Chromium Composition in %	Molybdenum Composition in %	Other Compositions in %	Remarks
1.4542	≤ 0.07	16.0	–	Ni: 4 Cu: 4.00	Used in aerospace. It is a precipitation hardening grade with very high strength.
1.4418	≤0.06	16.0	1.10	Ni: 2.00	It is the most resistant martensite against corrosion
1.4057	0.17	16.0	–	Ni: 2.00	Nickel replaces carbon for providing increased toughness and high ductility.
1.4125	1.10	17.0	0.60	–	Has a high resistance against wear. used as a tool steel grade (440C)
1.4122	0.40	16.5	1.10	–	Used in professional knives.
1.4104	0,14	16.5	0.40	S: 0.25	The addition of sulfur improves the machineability property.
1.4116	0.50	14.5	0.65	V: 0.15	Used in professional knives.
1.4021	0.20	13.0	–	–	It is a base grade used as stainless engineering steel.
1.4006	0.12	12.5	–	–	It is a base grade used as stainless engineering steel.

Mechanical Properties of Different Martensitic Steel Grades:

The following table enlists the mechanical properties of some common martensitic steel grades as per EN 10088-3 Standard.

EN Number	Tensile Strength in MPa	Minimum Elongation in %	Minimum Yield Stress in MPa	Heat Treatment
1.4542	960-1160	12	790	P960
1.4418	840-1100	16	700	QT900
1.0457	900-1050	12	700	QT900
1.4122	750-950	12	550	QT750
1.4021	650-850	12	600	QT800
1.4006	650-850	15	450	QT650

Physical Properties of Different Martensitic Steel Grades:

The following physical attributes of different Martensitic steel grades are as per the EN 10088-1 standard.

EN Number	Mean Coefficient of Thermal Expansion between 20°C and 100°C (10−6K−1)	Young’s Modulus at 20 °C (Gpa)	Thermal Conductivity at 20 °C (Gpa)	Electrical Resistivity (10−6Ω.m)	Specific Thermal Capacity at 20°C (Gpa)
1.4542	10.9	200	30	0.71	500
1.4418	10.3	195	30	0.80	430
1.4313	10.5	200	25	0.60	430
1.4057	10.0	215	25	0.70	460
1.4125	10.4	215	15	0.80	430
1.4122	10.4	215	15	0.80	430
1.4116	10.5	215	30	0.65	460
1.4021	10.5	215	30	0.65	460
1.4006	10.5	215	30	0.60	460

Processing of Martensite Steel Grades According to the Required Attributes:

Whenever there is a need for softness and formability in the fabrication, martensite steel with 0.12% Carbon (in soft condition) is used. When Carbon concentration increases, the tensile strength of 600-900 N/mm2 can be obtained by hardening and tempering. This steel with increased tensile strength also has reasonable ductility and toughness.

Also, lower ductility can be achieved in martensite steel that is:

• hardened,
• tempered,
• has a high carbon range, and
• tensile strength of 1600N/mm2.

Non-Destructive Testing of Martensite Steel:

As compared to austenitic steel, martensitic stainless steel can be tested non-destructively by a method known as magnetic particle inspection. Also, martensite steels can be hardened and heat treated. But when it comes to their chemical resistance, it is reduced as compared to their austenitic counterparts.

Learn here about 316L Stainless Low Carbon Austenite Carbon steels.

Applications of Martensitic Stainless Steels:

Based upon their carbon content, martensitic steels can be used in various places, such as:

Applications Requiring Resistance against Wear and Corrosion:

These include:

• Razor blades,
• Ball bearings,
• Medical tools (internal clamps, razors, surgical blades, scalpels),
• Cutlery,
• Brake disks included in motorbikes and bikes,
• Polymers and injection molds.

Applications as Corrosion-Resistance Engineering Steels:

Engineering martensitic steels are used in the manufacturing of

• Boat shafts,
• Valves, and
• Pumps

Other Martensite Grades:

Check out other materials made of martensite here:

ASTM F899 420A Martensitic Wrought Stainless Steels

440C Martensitic Stainless Steels in ASTM F899 Standard

42CrMo4 High Grade Molybdenum Alloy steel

ASTM F899 410 Martensitic Wrought Stainless Steels

UNS S17400 Stainless Steel Precipitation Hardening Grade

Suppliers for Martensitic Steel:

Material Grades helps industrialists choose the right vendors for their needs. That’s why we have listed some of the most authentic martensitic steel vendors here:

• Continental Steel and Tube Co. Address: Fort Lauderdale, FL, 33303, bearing contact number +1 954-332-2290
• All Metal Sales, Inc. Address: 29260 Clemens Road, Westlake, OH 44145, bearing contact number +1.888.333.0101.