Hardness Traverse (HAZ Traverse Testing)
Engineering definition, metallurgical mechanisms, standard testing specifications, and manufacturing guidelines for closed-die forgings up to 50 kg.
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A standardized series of closely spaced microhardness indentations measured across base metal, heat-affected zone (HAZ), and weld metal to verify hardness compliance.
Technical Explanation & Metallurgical Principles
Hardness traverse testing verifies that thermal cycles during welding or localized induction hardening do not create dangerously brittle microstructures. Per NACE MR0175 and ASME Section IX, Vickers or Rockwell hardness traverses must prove that no point in the heat-affected zone exceeds 22 HRC (250 HV10) to prevent sulfide stress cracking.
Key Engineering Specifications & Parameters
| Technical Parameter / Metric | Engineering Benchmark / Value |
|---|---|
| Indentation Spacing | 0.2mm to 0.5mm pitch across fusion boundary |
| Indenter | Vickers 10 kgf (HV10) or Rockwell C (HRC) |
| NACE Cap | Max 250 HV10 (22 HRC) in sour service weld zones |
Application at Jayesh Forge (Rajkot Plant)
Conducted in our Rajkot metallurgical lab for weld procedure qualifications (PQR) and induction-hardened gear prototypes.
Related Materials, Standards & Products
Related Metallurgical & Testing Terms
Vickers Microhardness Testing (HV)
A microhardness indentation test utilizing a square-based diamond pyramid indenter with a 136° apex angle to measure precise localized hardness across weld zones and cases.
Heat-Affected Zone (HAZ)
The portion of the base forging metal adjacent to a weld seam that has not melted but whose microstructure and properties have been modified by the intense heat of welding.
NACE MR0175 / ISO 15156 Sour Service Standard
The international standard defining material requirements for metallic equipment used in oil and gas production environments containing corrosive hydrogen sulfide (H2S).
Questions Regarding Hardness Traverse (HAZ Traverse Testing)
Peak hardness occurs in the coarse-grained heat-affected zone (CGHAZ) immediately adjacent to the fusion line due to rapid quenching of grain-coarsened austenite.
Request a Forging Quote with Hardness Traverse (HAZ Traverse Testing) Compliance
Our Rajkot metallurgy desk is ready to review your technical drawings, testing protocols, and delivery schedules for custom closed-die forgings strictly up to 50 kg.