Why Punches Fail In Production Skh51 Punch Material Selection And Heat Treatment Tips - China

SKH51 Punch Material – Root Causes Of Punch Failure And How To Get 3x Longer Life Every stamping shop knows the frustration: a punch that should last 100, 000 strokes starts chipping after 20, 000 - In most cases the failure is not bad luck — it is a combination of material condition, heat treatment and design details.

Here is how choosing the right SKH51 punch material (JIS standard, equal to AISI M2, DIN 1.3343 and GB W6Mo5Cr4V2) and treating it correctly can triple punch life.

Failure mode 1: Chipping at the cutting edge

- Cause: coarse carbide banding from insufficient forging, or too-high austenitizing temperature.

- Fix: request forged-and-annealed SKH51 with fine carbide distribution; quench from 1200–1220°C (not higher) in vacuum or salt bath.

- Our material: 7000-ton press forged, HB 255 max annealed, UT verified.

Failure mode 2: Wear on the punch flank

- Cause: working hardness too low or insufficient vanadium carbide volume.

- Fix: after quenching, triple temper at 550–580°C to reach HRC 63–65; avoid skipping the third temper — retained austenite shortens life dramatically.

- Our material: consistent chemistry (V 1.75–2.20%) batch after batch.

Failure mode 3: Total brittle fracture

- Cause: over-hardening, sharp internal corners in design, or grinding burn during finishing.

- Fix: specify toughness-optimized heat treatment (slightly lower hardness, HRC 61–63) for thick-sheet or off-center loading; add corner radii on drawings; use sharp grinding wheels with coolant.

- Our support: our engineers advise per application at no cost.

Recommended SKH51 punch material formats we supply:

- Ground round bars dia 3–80mm for turning punches in one setup

- Peeled rounds dia 10–200mm for larger pierce punches

- Flat and strip stock for punch plates and holders

- Cut-to-size blanks delivered ready for your heat treatment Every bar ships with mill certificate showing full chemistry (C 0.80–0.90 / Cr 3.80–4.40 / Mo 4.50–5.50 / W 5.50–6.75 / V 1.75–2.20), heat-number traceability, and optional SGS inspection.

Send us your punch drawing and current failure mode — we will recommend the right SKH51 format, starting size and heat treatment window within 12 hours.

Songshun Company Website: https: //songshunsteel.

com/

Company Contact:

• Posted By: Dongguan Songshun Mould Steel Co., Ltd.

• Phone: 0086 0769 85475596

• Address: 1st Floor, No. 1, Dongda Fourth Street, Shatou Community, Chang'an Town, Dongguan , GuangDong , China

• Email:

• Website: https://songshunsteel.com/

• Business Description: Established in 2009,Songshun Steel supplies a wide range of carbon, alloy and tool steel products, including high speed tool steel, cold work tool steel, hot work tool steel, plastic mould steel, engineering steel and machine structural steel etc.
  
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