What is the approximate pass rate for heat treatment of H13 material?

Under standard working conditions, the pass rate for heat treatment of H13 material can exceed 95%. The pass rate can be continuously maintained at about 98% if it is carried out by a qualified heat treatment facility with CQI-9 certification, the procedure is regulated, and all necessary documentation is kept.

 

1. Important Elements Influencing the Pass Rate

A factor

An explanation

Accuracy of Process Control

Deviations from the quenching temperature (1020~1050°C) and tempering temperature (550~600°C) must be ≤±10°C to prevent uneven hardness or cracking.

Medium State of Cooling

Regular inspection can boost the pass rate by 5% to 8%, but quenching oil water content greater than 0.5% will slow down cooling and raise the possibility of soft spots.

Structural Complexity of the Workpiece

Furnace loading techniques and cooling uniformity must be improved since thin-walled, porous, or asymmetrical constructions are prone to deformation.

Consistency of Raw Materials

Phase transformation behavior will be impacted by composition changes (e.g., Cr, Mo divergence >0.1%), which could result in overheating or incomplete quenching.

Actual Data: Over the course of the previous year, a Wuhan heat treatment facility with CQI-9 certification processed batches of H13 mold steel with an average pass rate of 97.6%.

 

2. Essential Steps to Increase the Yield Rate

Full-Process Monitoring: Keep track of each furnace's temperature curves to make sure holding times and heating/cooling rates satisfy process specifications.

100% Hardness Testing: After tempering, test each piece with a portable hardness tester to make sure the hardness is between 48 and 52 HRC.

Metallographic Sampling Verification: To verify uniform tempered martensite, do microstructure analysis on batch samples (≥5%).

Stress Relief Pretreatment: To lower the possibility of heat treatment deformation, perform stress relief tempering (500–600°C) following machining.

Case Study: By maximizing furnace loading density and gas circulation, Jingmo Technology lowered the deformation deviation rate of H13 nitrided parts from 4.2% to 1.1%.

 

3. Typical Signs and Repercussions of Nonconformities

A flaw

Expression

Danger

Inadequate Hardness (<45 HRC)

Over-tempering or insufficient quenching

Quick deterioration and collapse when in use

High Hardness (>54 HRC)

High residual stress and inadequate tempering

prone to cracking, particularly when injection molding pressure is high.

Unusual Microstructure

Network carbides and coarse martensite

Reduced resilience and increased chance of abrupt fracture

Decarburization or Surface Oxidation

A surface ferrite layer is shown by metallographic analysis.

Spalling failure due to poor adhesion following nitriding