Acidur 4122 QT750 Bar

Alternative and trade names
Acidur 4122


1.4122 (X39CrMo17-1) is characterised by its combination of outstanding mechanical properties, (after heat treatment) and a corrosion resistance which is comparable with that of 1.4016. This steel can also be polished to high gloss finishes.

Related Standards

Equivalent Materials



Density ρ

7.7 g/cm³ at 20 °C


Charpy impact energy, V-notch aK,charpy,V-notch

14 J at 20 °C

Elongation A5 A5

12 % at 20 °C

Hardness, Brinell HB

280 [-] at 20 °C


Tensile strength Rm

750 - 950 MPa at 20 °C

Yield strength Rp0.2 Rp0.2

550 MPa at 20 °C

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Coefficient of thermal expansion α

1.04E-5 1/K at 100 °C

for 20°C to the mentioned temperature

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Specific heat capacity cp

430 J/(kg·K) at 20 °C

Thermal conductivity λ

29 W/(m·K) at 20 °C


Electrical resistivity ρel

6.5E-7 Ω·m at 20 °C

Chemical properties


Weight %






15.5 - 17.5 %


1.5 %


1 %


1 %


Technological properties

Application areas

Automotive industry, Pump shafts, Food and Beverage industry, Mechanical engineering, Cutting Tools, Building industry

Corrosion properties

Good - As a result of its higher chromium content, 17 %, 1.4122 is more corrosion resistant than 1.4006 and other 13 % chromium stainless steels. Good corrosion resistance is displayed in moderately corrosive media/environments with low chloride ion concentrations. Although the addition of molybdenum increases the resistance of this steel to chloride containing environments, it is not suited for use in sea water applications unless it is provided with cathodic protection. Optimal corrosion resistance is attained when the surface is finely ground or polished. PRE = 18.47 – 20.46

General machinability

With Care - The machinability of this grade of stainless steel is directly related to its hardness and as such the optimal machining parameters vary considerably. Once the hardness is known, the machining parameters can be estimated since 1.4122 machines similar to carbon steels of the same hardness. Although it must be realised that the machining parameters will vary depending on the structure/hardness of the steel.

Heat Treatment

1.4122 can be soft annealed by holding at a temperature in the range 750 °C to 850 °C followed by slow cooling in air or in a furnace. 1.4122 can be hardened by holding at a temperature between 980 °C – 1060°C followed by cooling in oil or polymer. The tempering temperature is dependent on the desired strength. The heat treated condition usually specified is the QT750 condition and is obtained by tempering in the temperature range 650 °C to 750 °C.

Processing history

Quenched and tempered QT 750


With Care - This grade of steel is not usually welded, but if absolutely no alternative exists, then the workpiece is to be pre-heated to a temperature within the range 300 °C – 400 °C prior to welding. Since a large amount of untempered martensite will form in the heat affected zone, a subsequent tempering treatment will be required. Since this tempering treatment will over temper the already tempered martensite in the rest of the work piece, it would be preferable if the entire component were hardened and tempered, as described above. Once again, the time lapse between welding and heat treatment must be as short as possible to reduce the possibility of cracking. When the application of a filler metal is required, then Novonit® 4576 can be used.

This material data has been provided by Deutsche Edelstahlwerke Specialty Steel (DEW).

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.