420RM is a pre-hardened, martensitic stainless steel, with a good wear and erosion resistance and is frequently used in the plastic processing industry.
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420RM Stainless Steel Standard values
Working hardness:
approx. 30 HRC (delivery condition) - 48 HRC
Delivery condition:
max. 325HB
Chemical composition in %
0.330000
0.330.450000
0.450.000000
01.000000
10.000000
01.500000
1.50.000000
00.045000
0.0450.000000
00.030000
0.0315.500000
15.517.500000
17.50.800000
0.81.300000
1.30.000000
01.000000
1420RM Stainless Steel Technical Data
420RM Stainless Steel Technical Properties
Pre-hardened corrosion resistant chrome-steel with good polishing properties, heat resistance and wear resistance. Often used for processing chemically aggressive plastic materials (e.g. PVC). The material is conditionally acid resistant.
420RM Stainless Steel Applications
mechanical engineering, marine engineering, apparatus engineering, plastic processing, plastic molds, extrusion tools, press molds, fitting tools, shafts, spindles, bolts, pistons, valves, steam valves, water valves, beater bars, fittings parts, pump construction, pump rods, compressor construction, compressor parts, surgical Instruments
420RM General Information
420RM shows outstanding mechanical properties with good corrosion resistance that can be polished to a high gloss finish. Due to the added chromium, up to 17%, it has a higher corrosion resistance compared to stainless steels with for example 13% of chromium. Tough it has a good corrosion resistance this stainless steel should not be used in seawater but can be used in freshwater for valves or pump shafts for marine- or mechanical engineering for instance.
Corrosion resistance
As a 17% chromium steel 420RM has a higher corrosion resistance compared to 410 stainless steel, a 13% chromium steel. In moderately corrosive environments with low chloride ion concentration 420 RM shows good corrosion resistance, this is increased further with the addition of molybdenum but with out further protection against corrosion, e.g. cathodic protection, this steel is not suitable for sea water. Corrosion resistance can further be enhanced if the surface is finely ground or polished.
Heat treatment
Annealing
Heat the material uniformly to a temperature of 138-1508°F (750-820°C) and hold for 2 to 4 hours. Following this, finish the process by a slow cooling in the furnace or in air.
Stress relieving
Uniformly heat the parts to a temperature of 1112-1202°F (600-650°C), follow this with a cooling in the furnace.
Hardening
Slowly and uniformly heat the work pieces to a temperature of 1796-1940°F (980-1060°C) hold and quench.
Quenching media
- Air
- Oil
- Salt- or polymer bath
Tempering
Heat the material to a tempering range of 1202-1382°F (650-750°C) then cool in air.
Care has to be taken to temper the material as soon as possible after hardening to avoid possible cracking.
Machinability
Forging
Slowly preheat the parts to a temperature of 1472°F (800°C), then more rapidly heat to 2108-2156°F (1150-1180°C). Forging is done in the temperature range of 2156-1742°F (1180-950°C), do not let the temperature drop below 1742°F (950°C). Cool the parts in the furnace, dry ash or similar materials promoting slow cooling.
Welding
420RM is not normally welded. If welding is necessary the steel should be preheated to a temperature range of 572-752°F (300-400°C). Since a large proportion of non-tempered martensite form in the heat affected zones, it is necessary to temper the material after. As during the tempering treatment, the martensite’s of the rest of the work piece are being over-tempered, it is advisable to follow the hardening and tempering processes as stated above.
As in the tempering step it is important to commence with the heat treatment as close as possible to finishing the welding process to reduce the possibility of cracking.
Disclaimer
The data shown here has been compiled with the greatest diligence and is regularly updated with regard to the correctness and completeness of its content. The content is indicative only and should not be taken as a warranty of specific properties of the product described or a warranty of suitability for a particular purpose. All information presented is given in good faith and no liability will be accepted for actions taken by third parties in reliance on this information. ABRAMS Industries reserves the right to change or amend the information given here in full or parts without prior notice.