Stamping Die Heat‑Treatment Process Standardization & Optimization Project

Case Implementation Cycle: July 2025 – August 2026 (14‑month continuous mass‑production verification)

This surveyed enterprise is an auto‑component stamping manufacturer in Pearl‑River Delta region. Main products are high‑strength‑steel structural‑stamping‑parts for new‑energy vehicles. The workshop owns 48 sets of mass‑production stamping dies, most of which adopt Cr12MoV tool‑steel. Before optimization, all die heat‑treatment processes were outsourced to three external third‑party heat‑treatment factories. The main pain‑points included large fluctuation of die service‑life, frequent early‑stage chipping and cracking failure, high die‑repair workload, frequent unexpected production downtime caused by die failure, and high per‑part die‑amortization cost. In July 2025, the enterprise carried out comprehensive heat‑treatment‑process standardization transformation: formulated exclusive process specification for different die‑steel grades, selected qualified heat‑treatment cooperative‑suppliers with whole‑process‑recording capability, formulated incoming‑inspection standards beyond simple hardness‑testing, and standardized heat‑treatment requirements for post‑welding repaired dies. After 14‑month stable‑mass‑production operation, complete measured‑data statistics and comprehensive‑benefit evaluation were completed.

A1: The measurable economic benefits are divided into four parts. First benefit: reduce new‑die‑replacement frequency owing to die‑life extension, accounting for 49% of total annual benefit. Second benefit: sharp drop of die‑repair times, saving repair‑welding, component‑replacement and labor‑cost for die‑shop, accounting for 31%. Third benefit: reduce production‑loss caused by unexpected die‑failure downtime, accounting for 14%. Fourth benefit: reduce new‑die scrapping loss caused by heat‑treatment deformation, accounting for 6%. The project does not add large‑scale hardware‑investment; main cost‑increase comes from higher‑standard external heat‑treatment processing‑fee and internal‑management labor input. After offsetting incremental cost, the net annual measurable economic benefit reaches USD 124 300. Implicit benefits include production‑line OEE improvement, stable part‑quality consistency and reduction of customer complaint risk caused by burr‑defect from die‑abnormal‑wear.

A2: Two main obstacles existed. First, partial original cooperative heat‑treatment factories were unwilling to provide complete temperature‑curve record file, because standardized multi‑tempering process will extend processing cycle and raise their production‑cost. The enterprise eliminated two old suppliers and re‑screened qualified suppliers with standardized‑process capacity. Second, internal department‑coordination difficulty: purchasing department faced higher unit‑processing‑cost; die‑shop worried about longer delivery cycle of dies. The project team organized data comparison meeting, displayed historical statistical data of huge loss caused by non‑standard heat‑treatment, and reached consensus among purchasing, die‑shop, production‑department. Meanwhile, through order‑quantity‑integration negotiation with new suppliers, the enterprise controlled the increase range of heat‑treatment unit‑price within 7.2%, avoiding excessive rise of single‑die‑manufacturing‑cost.

A3: Before optimization, after die edge chipping, workshop directly carried out surfacing‑welding repair and put die back into production without stress‑relief treatment. Local high‑temperature welding produces huge welding residual‑stress inside die steel. Under stamping cyclic impact load, repaired position is easy to crack again in short‑term, many dies repeatedly fail at same welding‑repair position. After adding mandatory post‑welding stress‑relief tempering procedure, the re‑failure rate of welding‑repaired dies within 50 000 strokes dropped from 34.6% down to 5.3%. It avoids repeated repair‑loop of same die, greatly reduces invalid die‑repair workload.

A4: Three‑layer control‑mechanism is established. First, technical‑agreement binding: detailed heat‑treatment technical‑index and deliverable‑requirement are written into purchasing‑contract, incomplete temperature‑curve file is regarded as unqualified delivery, suppliers cannot settle payment normally. Second, incoming‑quality‑spot‑check mechanism: quality‑department carries out multi‑point hardness test and sampling metallographic inspection randomly, for dies from each batch of heat‑treatment. Third, closed‑loop feedback mechanism: according to die‑life tracking file, if individual die appears early‑failure, firstly trace its heat‑treatment curve record, judge whether heat‑treatment‑process is abnormal, and feed back to supplier for process rectification. Through contract constraint, quality‑inspection and failure‑trace‑ability, avoid process‑standard degradation in long‑term mass‑production.

A5: First, do not only focus on single hardness‑value index, pay attention to tempering times, cooling‑mode and whole‑process temperature‑curve trace‑ability. Second, classify dies according to production‑volume; high‑volume key‑production dies should implement strict standard; for low‑volume trial‑production dies, balance cost‑input reasonably. Third, must cover repair‑welding links, not only focus on new‑die manufacturing. Fourth, build internal die‑life‑statistic database, use real‑mass‑production data to evaluate actual improvement effect after process adjustment, rather than only rely on theoretical‑parameter of suppliers. Fifth, carry out supplier‑capability assessment in advance, confirm whether cooperative‑factory has equipment‑condition to realize target‑process, avoid writing high‑standard specifications which cannot be realized in actual processing.

This 14‑month full‑cycle mass‑production verification shows that heat‑treatment‑process standardization and optimization is a high‑return invisible‑core‑link upgrading project for stamping enterprises, especially for factories undertaking high‑strength‑steel and high‑volume stamping‑business. It solves many long‑term‑existing pain‑points including large die‑life fluctuation, frequent early‑stage chipping‑cracking failure, high die‑repair workload and high per‑part die‑amortization‑cost. It brings considerable comprehensive economic benefits without large‑scale equipment‑retrofit investment. Meanwhile, it stabilizes stamping‑part quality consistency, reduces unexpected production‑interruption risk, improves production‑line OEE performance. With the continuous popularization of high‑strength‑steel stamping‑application in new‑energy‑vehicle industry, higher requirements are put forward for anti‑wear and anti‑impact performance of stamping dies. Heat‑treatment‑process management capability will gradually become one of the important soft‑power indicators for high‑level stamping‑manufacturers.