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1.2379 Material - Full Testing Guide for Tool Steel

Is the 1.2379 material you received qualified? This article breaks down the full process, from visual check and dimension measurement to chemical composition test, ultrasonic test, metallographic test and hardness test.

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1.2379 Material
Material 1.2379
1.2379 Steel
1.2379 Tool Steel
DIN 1.2379

Surface and Size Check of 1.2379 Material

Surface

Look at the material surface for cracks, folds, scabs and pressed-in scale. Hot rolled or forged 1.2379 steel normally has black skin or smooth surface. Make sure there are no serious surface defects. We suggest customers mill or turn the surface, so defects can be easily seen.
 

Size

DIN 1.2379 can be supplied as round bars, plates and blocks. Round bar diameter: 10–300 mm. Flat steel thickness: 20–400 mm, width:210–610 mm. Length:3000–5800 mm. Check diameter/thickness, tolerance, length and straightness against your order.

Chemical Composition Test of 1.2379 Material

Handheld XRF

After receiving 1.2379 material, test its composition with handheld XRF. Handheld XRF can quickly measure metal elements such as Cr, Mo, V, Ni, W, Mn. Results come out in seconds.
 

OES Optical Emission Spectroscopy

Bench-top OES in the lab can accurately test metal elements Cr, Mo, V, Ni, W, Mn. It also detects non-metal elements including C, Si, P, S.
 

1.2379 Steel Composition(DIN 17350-1980)

  • C: 1.50–1.60%
  • Si: 0.10–0.40%
  • Mn: 0.15–0.45%
  • P: ≤0.030%
  • S: ≤0.030%
  • Cr: 11.00–12.00%
  • Mo: 0.60–0.80%
  • V: 0.90–1.10%

We focus mainly on checking P and S. For 1.2379 steel, P must be ≤0.030%, and S must be ≤0.030%. Too much P causes cold brittleness. Too much S causes hot brittleness. If these two items fail, 1.2379 material will have problems with toughness and hot workability.

Metallographic Test of 1.2379 Steel

Sample preparation: cut sample → mount → grind → polish → etch. The etchant is 4% nitric acid alcohol solution.

Carbide Non-uniformity

  • The wear resistance of DIN 1.2379 steel comes from carbides. But uneven carbide distribution will badly hurt toughness and polishing performance. Carbides may show banded or network segregation.
  • Test method: Grind and polish metallographic sample. Etch it with 4% nitric acid alcohol solution, then check carbide shape and distribution. Reference standard GB/T 1299-2008.
 

Decarburization Depth

  • During forging or rolling of 1.2379 material, carbon on the surface may burn away and form decarburized layer. Decarburized layer has low hardness and poor wear resistance. If it is not fully removed in machining, soft spots will appear on mold surface.
  • Decarburization depth must be within machining allowance. When you buy bright surface material, decarburized layer is fully removed. (This is why we usually suggest bright surface material.)
  • Test standard: GB/T 224-2019 (Determination of decarburized layer depth of steel) or ISO 3887:2017. Use metallographic method or hardness method for measurement.

Non-metallic Inclusions

  • Rating types: Type A (sulfides), Type B (alumina), Type C (silicates), Type D (globular oxides). The lower the grade of each type, the higher the purity.
  • Test standard: ASTM E45 Method A (most commonly used) or DIN 50602.

Grain Size

Measure average grain size according to ASTM E112. Standard 1.2379 tool steel from Keyspark Steel usually has grain size No.6–8. If you need higher standard, we can provide custom ESR service for finer grain size.

Hardness Test of DIN 1.2379

Delivery conditions of 1.2379 material include annealed and QT. Most customers require Keyspark Steel to supply DIN 1.2379 in annealed condition.

Annealed Condition

  • Test method: Brinell hardness tester (HBW), indenter diameter 10 mm, test force 3000 kgf.
  • Standard requirement: Hardness in annealed condition ≤255 HB.
  • Soft annealing process for material 1.2379: Heat to 830–860°C, cool slowly to 600°C at 10–20°C per hour, then cool in air.
 

QT Condition

  • Test method: Rockwell hardness tester (HRC).
  • Standard requirement: Hardness after quench and temper 58–62 HRC. It can reach 62–64 HRC under extreme conditions.
  • Reference heat treatment process for 1.2379 steel: Quench at 1020–1040°C, cool in oil or air. Temper at 180–250°C, hardness reaches HRC 62–63 (temper at 100°C).

FAQ of 1.2379 Material

Q1: What are the common reasons for failed inspection of 1.2379 Material?

A: Common reasons include chemical composition deviation, excessive annealed hardness, unsatisfactory ultrasonic test grade, high carbide non-uniformity rating or too deep decarburized layer.

A: SEP 1921 is a German standard, graded by Class D/d, E/e. ASTM A388 is an American standard, and acceptance requirements are shown by defect equivalent size. They share the same test principle, but use different grading systems.

A: For chemical composition sampling, stay away from surface oxide layer and decarburized layer. Metallographic samples should be taken from positions that can show the worst structure. Ultrasonic test scans the whole 1.2379 mold steel.

A: Check whether annealing temperature, holding time or cooling rate meet requirements. If the material is not machined, re-do soft annealing: heat to 830–860°C, cool slowly to 600°C at 10–20°C per hour, then cool in air.

A: Optical emission spectrometer for chemical composition test. Brinell and Rockwell hardness testers for hardness test. Ultrasonic flaw detector for internal defect test. Metallographic microscope, cutting machine, mounting press, grinding and polishing machine and 4% nitric acid alcohol solution for metallographic test.

A: Decarburized layer reduces surface hardness and wear resistance of molds. If it is not fully removed, soft spots will form on mold surface and shorten service life.

Conclusion

From chemical composition, hardness and ultrasonic test to metallography and mechanical properties, the inspection of 1.2379 material decides the final service life of molds. Keyspark Steel offers inspection and quality guarantee support for DIN 1.2379 steel. We also provide custom ESR grade material with quality guarantee. We supported more than 50 customers from Europe, South America, Middle East and Africa. We help you lower 1.2379 steel selection risks during purchase, and make material performance fully traceable and verifiable.

More 1.2379 Material Resources

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