SCMn2

What is SCMn2 steel?

SCMn2 is the Japanese (JIS) designation for a manganese structural steel. Cross reference tables put it against EN grade 28Mn6, material number 1.1170. Its strength comes from manganese at 1.30 to 1.65 % together with 0.25 to 0.32 % carbon. Chromium, nickel and molybdenum are all held down to residual levels, with a combined maximum of 0.63 %.

Manganese raises hardenability at a lower cost than a fully alloyed steel, so SCMn2 holds reasonable strength through medium sections while staying machinable and weldable. Buyers usually reach for it when a plain carbon steel such as C45 will not harden far enough into the section, and a chromium molybdenum grade such as 42CrMo4 is more steel than the duty needs.

Strengths and limitations of SCMn2

• High hardenability for its alloy content, with fairly small quenching distortion.
• Good static and fatigue strength after quenching and tempering.
• Acceptable machinability. Weldable if preheated above 200 °C.
• Sensitive to overheating and to surface decarburisation, so forging and reheating temperatures need to be controlled.
• Prone to temper brittleness. Avoid tempering in the embrittlement range and cool quickly from tempering temperature.

SCMn2 chemical composition

The table gives ladle analysis limits for SCMn2 / 28Mn6. Actual heat analysis is stated on the mill test certificate that ships with every order.

SCMn2 mechanical properties

Section size drives the mechanical properties of SCMn2, because heavier sections cool more slowly and finish lower in strength. Values below are for the normalised (+N) condition unless noted.

Tensile and yield strength by section size

Impact toughness

Physical properties

SCMn2 hardness

Maximum hardness for SCMn2 depends on delivery condition. Material treated to improve shearability (+S) is allowed to run harder than soft annealed (+A) material.

SCMn2 equivalent grades

SCMn2 cross references to the grades listed below. Treat them as close matches rather than exact ones, since composition limits and test requirements differ between standards. Check the grade and standard called up on your drawing before ordering.

SCMn2 heat treatment and forging parameters

Use the figures below as starting points. We set the actual cycle for each part according to geometry and section size, and the furnace chart goes out with the order.

SCMn2 does not tolerate overheating or long soaks. Keep it inside the forging range, and leave enough machining allowance to take off any decarburised surface layer.

SCMn2 forgings we manufacture

We make the following forms in SCMn2, to customer drawing, rough machined or finish machined. Our shop runs 1, 3, 6 and 9 ton hammers with a 4500 ton hydraulic press, plus 3 metre and 6 metre seamless rolled ring mills. Across all grades we cover diameters from 100 mm to 6000 mm, lengths from 100 mm to 12000 mm and piece weights from 10 kg to 15000 kg.

• SCMn2 forged bars

  Round, square, rectangular, flat and hexagonal bars for shafts, pins and machined parts. Round 100 to 1200 mm dia., length to 12000 mm

• SCMn2 seamless rolled rings

  Radial axial rolled blanks for bearing races, slewing rings, flanges and gear blanks. OD 200 to 6000 mm, height to 1000 mm

• SCMn2 forged rings and flanges

  Upset and punched rings where ring rolling is not economical, plus heavy flanges. OD 200 to 3000 mm, wall to 500 mm

• SCMn2 hollow bars, sleeves and bushings

  Bored and trepanned hollows, cylinders, shells, casings, housings and hubs. OD 150 to 2000 mm, ID from 60 mm

• SCMn2 blocks, discs and plates

  Upset discs, rectangular blocks and forged plate for die bases, tooling and end covers. Thickness 50 to 800 mm, piece weight to 15000 kg

• SCMn2 gear shafts, pinion shafts and spindles

  Stepped and flanged shafts for gearboxes, drive trains and rolling mill spindles. 100 to 1000 mm dia., length to 10000 mm

Sizes outside these ranges are often still workable. Send a drawing or a sketch with grade, quantity and delivery condition and we will confirm.

Production and inspection of SCMn2 forgings

Every SCMn2 order runs through the same route from steel to shipment.

1. Steelmaking EAF with ladle furnace and vacuum degassing for SCMn2. ESR, VIM and VAR routes are available where a cleaner steel is specified.
2. Heating and open-die forging Heated into the 1050 to 850 °C range and worked on hammer or press to reach the forging reduction ratio agreed for the part.
3. Ring rolling For rings, the pierced preform is rolled radially and axially to near net size on the 3 or 6 metre mill.
4. Heat treatment Annealing, normalising, or quenching and tempering, with a charted furnace record for each load.
5. Testing Chemical analysis, tensile, impact and hardness testing, with ultrasonic examination to the acceptance class stated on the order.
6. Machining and dispatch Rough or final machining to drawing, marking, then shipment with an EN 10204 3.1 or 3.2 certificate.

Third party inspection by SGS, BV, TUV or a classification society can be arranged when the buyer requires it.

What is SCMn2 used for?

SCMn2 fits moderately stressed parts that need dependable strength through the section without paying for a chromium molybdenum steel. Common uses include:

• Cardan shafts, camshafts and drive shafts in vehicle and engine manufacturing
• Gear wheels, gear blanks and pinion shafts in general machine engineering
• Slewing rings, bearing races and flange rings
• Cylinders, sleeves and housings for hydraulic and mechanical equipment
• Shafts and rings for pumps, compressors, gearboxes and mixers
• Welded fabrications and pressure retaining parts needing better notch toughness below ambient temperature

Questions about SCMn2

About the manufacturer

Page last reviewed 15 September 2026 by the technical sales team at Jiangyin Jiangnan Metal Co., Ltd. Property data is taken from EN 10083-2:2006 and published mill datasheets for 28Mn6 / 1.1170, and is given for guidance. Acceptance criteria for an order are agreed in writing.