42CrMo4 High Grade Molybdenum Alloy steel

What is 42CrMo4? This Grade is the special high steel grade which can be quenched and tempered. It offers a robust amalgamation of strength and toughness in the state of being quenched and tempered. Different European standards cover the specification of this steel in different forms and processing conditions. The steel can be subjected to induce hardening. This steel grade is usually available in a mix of microstructure i.e. martensite and austenite. The special grade of this steel is subjected to M-treatment to offer good machinability properties.

What is EN 10083? EN10083 is a European standard developed in the year 2006 by different member countries of European nation states.  The standard is titled as “Steels for quenching and tempering. Technical delivery conditions for alloy steels.” 42CrMo4 is defined in EN 10083 standard.  There are other European standards as well for other forms of 42CrMo4 which are listed as under:

  • EN 10132-3: 2000 titled as “Cold rolled narrow steel strip for heat treatment.”
  • EN 10305-1 published in the year 2010. Titled as “Steel tubes for precision applications. Seamless cold drawn tubes”.
  • EN 10269 published in the year 1999 titled as “Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties”.
  • EN 10263-4 published in the year 2001 titled as “Steel rod, bars and wire for cold heading and cold extrusion”.
  • EN 10250-3 published in the year 2000 titled as “Open steel die forgings for general engineering purposes”.
  • EN 10297-1 published in the year 2003 titled as “Seamless circular steel tubes for mechanical and general engineering purposes. Non-alloy and alloy steel tubes.”

Why 42CrMo4 called Grade 4142 high grade steel? When a material grade is specified as high grade steel, it means it has robust characteristics due to chromium. However this grade has also for molybdenum in it that makes it different. 42CrMo4 is the UNS designation alloy, also referred as 4142 alloy in SAE designation.

Available Forms in Market: Following are the available forms of 42CrMo4 steels in the global market as per different European standards:

  • Cold rolled narrow steel strip
  • Steel tubes
  • Rods, Wires and bars
  • Steel Die forgings
  • Seamless circular steel tubes
  • Cold redrawn forms
  • Flat plates

Dimensional Characteristics of 42CrMo4 Steels: 42CrMo4 is available in round bar Sizes from diameter of 10 millimeters to 3000 millimeters. It is also available in the form of Flat Plate in the thickness of 10 millimeters to 1500 millimeters and width of 200 to 3000 millimeters width, other steel shape and sizes available according to your requirements. Other forms can be inquired from suppliers.

Compare 42CrMo4 high grade steel with UNS S31603 Austenitic Molybdenum Stainless Steel

The Indicative Chemical Composition of 42CrMo4 Steels:  The chemical composition of this grade is indicated as under:

  • Maximum percentage of Carbon (C) is 0.45 percent and minimum percentage is 0.38.
  • Maximum percentage of Manganese (Mn) is 0.9 percent and minimum percentage is 0.60.
  • Maximum percentage of Phosphorous (P) is 0.035 percent.
  • Maximum percentage of Sulphur (S) is 0.035 percent.
  • Minimum percentage of Chromium is 0.90 percent and maximum percentage of Chromium is 1.2 percent.
  • Maximum percentage of Silicon (Si) is 0.40 percent.
  • Maximum percentage of Molybdenum (Mo) is 0.30 percent and minimum is 0.15 percent.

Remaining is iron (Fe) percentage and with few negligible impurities.

Mechanical Properties of 42CrMo4 Steels: Following are some of the mechanical properties of 4142 steels:

  • The tensile strength of this grade alloy steel is expressed in Newton per millimeters and it must be at-least 1000 N/mm2 (MPa).
  • The elongation property of 42CrMo4 steel varies with the heat treatment process and thickness but it is indicated typically 11%.
  • 42CrMo4 can be welded by all fusion and resistance methods. But it is not weld able with oxyacetylene welding methods.
  • The yield strength of this grade alloy steel is expressed in Newton per millimeters and it must be at-least 550 N/mm2 (MPa).
  • High grade steel 42CrMo4 has very low weldability. A process of preheating the base steel to 200 to 300°C is extremely. The temperature should not exceed from this range as it can damage chrome layer.
  • Alloy grade 42CrMo4 can be welded with the help of friction. But, precautions are needed so as to resists the growth of unwanted weakening microstructures in the zone of weld.
High Grade Steel

Round bars of 42CrMo4

Heat Treatment of 42CrMo4 Steels:

42CrMo4 steels can be annealed, quenched, and forged. A brief guideline on the subject is provided below:

Annealing of 42CrMo4 Steels

Annealing should be done on this type considering below parameters:

  • Heat steel grade 42CrMo4, Slowly and gradually forge it in the desired and do it comprehensively with the temperature range of 800-850°C
  • Slowly and gradually cool the furnace to the temperature of Celsius 480°
  • Allow it to cool slowly i.e. annealing the steel in the air.

Quenched and Tempered (Q+T)

Quenched and tempering should follow this course;

  • Heat material grade 42CrMo4 slowly to Celsius 880°
  • Soak the steel in oil at this temperature in order to quench it
  • As the steel reaches the room temperature, temper it by heating it to a desirable temperature of five hundred and sixty degree Celsius.
  • Take off the 42CrMo4 grade alloy from the furnace and allow it to cool in the air.

Forging of 42CrMo4 Alloy Steel

This process should be done by following these steps:

  • Allow the steel grade 42CrMo4 to be slowly preheated with uniformity
  • Elevate the forging temperature to the range of Celsius i.e. 1150-1200°.
  • Make sure to maintain the temperature of forging beyond Celsius 850°

Equivalent Material Grades in Other International Standards:

  • Equivalent grade of this type in SAE is 4140 and 4142 type steel
  • In JIS designation, the corresponding material is referred as SCM440H alloy.
  • In DIN standard, the corresponding material is referred as 1.7225 type steel.
  • In Swedish SS standard, the corresponding material is referred as 2244 type steel.

Applications of 42CrMo4 High grade steels: Applications are as under:

  • Parts of axle shafts
  • Different types of gears such as gear wheel of engine, driving gear of super charger etc.
  • Parts of crankshafts
  • Mining spare parts
  • Equipment in power train
  • Induction hardened pins
  • Fastener accessories
  • Drilling equipment in oil and gas such as drill collars

Suppliers of 42CrMo4 Steel: Suppliers are also listed below:

Supplier Hillfoot bearing contact number +44 (0) 114 233 1133.The supplier address is Head Office Herries Road, Sheffield, South Yorkshire. Postal code is S6 1HP.

Supplier Otai Steel bearing contact number +86 136 1014 9979.The supplier address is 3#,Xiansha, Gaobu town, Dongguan, Guangdong Province. P.R. China.

Leave a Reply