Stainless Steel Grade AISI S165M (SS 2387) | EN 1.4418

AISI S165M (SS 2387) | EN 1.4418 | DIN X4CrNiMo16-5-1 - corrosion- and acid-resistant soft martensitic chromium-nickel-molybdenum steel. It has a martensitic-austenitic-ferritic mixed structure. It is characterized by very good resistance to corrosion in aggressive environments, good mechanical and impact properties.

Often used in mechanically and corrosively loaded components such as water turbines in the chemical industry, pump shafts, centrifuge parts, automotive and aerospace industries.

EN 1.4418 demonstrates higher corrosion resistance compared to other martensitic stainless steel grades due to the higher content of alloying elements. It is also not subject to intercrystalline corrosion and has good fatigue strength. Due to the low carbon content, EN 1.4418 has good weldability by all standard methods. And the addition of molybdenum to its composition helps limit the negative impact of the marine environment.

Welding

Easily welded by all standard welding methods. However, care should be taken that hydrogen or carbon-containing gases are not used when welding under shielded gas. Preheating of the workpiece to a temperature of 100 °C to 200 °C is recommended. After welding, the material should be annealed or hardened. If a filler material is required, an appropriate filler should be used.

Forging

When forging this grade of stainless steel material, it is recommended to first gradually heat it to a temperature of about 800 °C before heating it more rapidly to a temperature of 1150 °C to 1180 °C. Forging takes place between 1180 °C and 950 °C. This is followed by cooling in a furnace in dry ash or similar material to facilitate slow cooling.

Processing

The machinability of this grade of stainless steel is directly related to its hardness. The machining process is similar to the machining process of carbon steels with approximately the same hardness. The machining parameters will vary depending on the heat treatment conditions and the hardness of stainless steel AISI S165M (SS 2387) | EN 1.4418 | DIN X4CrNiMo16-5-1.

Physical properties

Table No. 1: physical properties of stainless steel grade AISI S165M (SS 2387) | EN 1.4418 | DIN X4CrNiMo16-5-1
Density g/cm³	7,7
*Specific heat capacity at +20°C, J/kgK**	430
*Thermal conductivity at +20°C, W/mK**	15
*Specific electrical resistance at +20°C, μOhmm**	0,80
Magnetic properties	magnetic

Table No. 2: physical properties of stainless steel grade AISI S165M (SS 2387) | EN 1.4418 | DIN X4CrNiMo16-5-1
Temperature	+20°С	+100°С	+200°C	+300°С	+400°С
Modulus of elasticity, GPa	200	195	185	175	170
Coefficient of linear expansion, 10^-6/°C	10,3	10,3	10,8	11,2	11,6

Table: chemical composition of steel grade AISI S165M (SS 2387) | EN 1.4418 | DIN X4CrNiMo16-5-1
Chemical composition of steel grade AISI S165M (SS 2387) \| EN 1.4418 \| DIN X4CrNiMo16-5-1
C	Si	Mn	P	S	Cr	Mo	Ni	N	Fe
<0,06	<0,70	<1,5	<0,040	<0,015	15,0-17,0	0,80-1,50	4,0-6,0	>0,020	Other

In the standard state, the structure consists of 80% martensite, 10% austenite and 10% ferrite. This composition provides a low-carbon martensitic structure after quenching. Martensite, some remaining austenite, chromium and molybdenum together give the steel the following characteristic properties:
- high tensile strength;
- high toughness;
- excellent surface anti-corrosion properties;
- better corrosion properties than most existing martensitic stainless steels;
- very good fatigue resistance;
- wear resistance;
- suitability for lubrication.

Applications

- piston rods;
- marine environment;
- extreme climate conditions;
- mining;
- road machinery;
- chemicals;
- civil engineering.

- agricultural machinery;
- heavy industry;
- hydraulic systems;
- environmental protection;
- aircraft manufacturing;
- aerospace industry;
- nuclear power.