Technical Information - Special Steel (hardened) 420 + Mo

Basic Information and Applications 420 + Mo

Due to the alloy with 13% chromium and 1% molybdenum, this alloy is corrosion-resistant in moist air, water vapor and water, but not sufficiently resistant to chloride ions and acids.
The advantages of this steel are its good wear resistance and minimal internal stresses. With a tensile strength of 1700 to 1950 N / mm², this material is ideal for springs, gauges, tools and knives.

The rustproof, hardened knife steel 420 + Mo is available in thicknesses from 1.0 mm.

Further areas of application: Knives and saws in the food industry, scalpels, textile knives, wear strips, pressure squeegees, shock absorber valves and reed valves for compressors.

The comparable material 420 is approved as spring steel strip in the DIN EN 10 151 standard. The material we offer also has a molybdenum content of approx. 1%, which improves corrosion resistance.
It is also suitable for high mechanical loads and has a high fatigue strength and is the only stainless steel used for shock absorber valves and reed valves.

If there are high demands on hardness and wear resistance, grade 1.4112 should be used.

Delivery condition

Structure: hardened and tempered
Surface: polished white - Ra 0.1-0.25 µm, mean value 0.16 µm -  Ra 0.20 - 0.50 µm (depending on thickness)
Tensile strength: 17-1900 N / mm² 

Tolerances

Thickness tolerance: T1 to T3 depending on the available raw material
Width tolerance: B1
Straightness: normal
Flatness: P2 (0.3% of the bandwidth), partly also P3 (0.2% of the bandwidth)

Flatness P3 and a polished surface Y8 are necessary for use as a reed valve in compressors.

mechanical Details

Yield strength Rp0.2: >1450 N / mm²
Elongation A 80: no values ​​available
Fatigue limit: high fatigue limit, suitable for shock absorbers or reed valves.

Alloy Designations

Material - Composition *

* for the exact composition can be documented in the form of a test certificate 2.2 or 3.1 (according to DIN 10 204) for each batch.

Physical Information

Processing information 420 + Mo

Punching: The cutting gap should be about 10% of the tape thickness. The corner radii should be at least 0.25 and the punch diameter at least twice the tape thickness. After punching, the parts can be heat-treated to relieve tension at a maximum temperature of 250 ° C and a duration of approx. 30-60 minutes.

Post-treatment by vibratory grinding is necessary for stamped parts to achieve good fatigue strength.

Laser cutting: The melting of the steel at the cutting edge can locally lead to a higher hardness and thus reduced toughness at the cutting edge. A cut with a water jet is recommended for critical parts.

Etching: The material 420 + Mo can be etched very well.

Bending: The band structure is changed by the hardening process. This means that the rolling direction does not have to be taken into account when edging:

Bending radius:

- at least 5 times the tape thickness up to a thickness of 0.25 mm

- at least 5 times the tape thickness from 0.30 mm to 0.50 mm

- at least 12 times the tape thickness over a thickness of 0.60 mm

Springback:

As the springback depends on various factors, bending tests should be carried out. As a guide, an angle of 10 ° for a tape thickness of 0.20 mm and an angle of 20 ° for a tape thickness of 0.60 mm can be assumed.

Surface grinding: The material 420 + Mo is magnetizable and can therefore be clamped on magnetic clamping plates of grinding machines.

Welding: Since the martensitic chromium steels are air-hardening, welding is very difficult.

Chemical Resistance 420 + Mo

Allocation to group 1 of the Nirosta table for the chemical resistance of stainless steels (see www.nirosta.de/Publikationen). This material is therefore less corrosion-resistant than the materials 1.4310 (group 4) and 1.4404 (group 5).

Nirosta is a registered trademark of ThyssenKrupp AG.

Please check there or through a test whether the material 420 Mo is sufficiently resistant for your application.

Important NOTE

The technical information listed above or the information provided on the nature or use of the materials serve for description and are not a guarantee of properties. The information with which we want to advise you corresponds to our experience and that of our upstream suppliers. We cannot guarantee the results of processing and application. (03/2024)