Stress Intensity Weldability Threshold
The stress intensity weldability limit is a fracture mechanics limit that assesses crack propagation under residual stresses after welding. It helps minimize risk for materials prone to brittle fracture.
Physicochemical Mechanism of Action
The stress intensity weldability limit (SIWL) describes the maximum stress intensity under which a material is still fracture-resistant after welding. It takes into account the local stresses and their effect on crack propagation.
Metallurgical Relevance & Welding Risks
If the actual stress intensity in the weld exceeds the SIWL, brittle fracture can occur. This raises the risk of cracks and cold fractures, especially for highly fracture-prone materials like high-strength nickel alloys and ferritic steels.
Workshop Practice & Instructions
To respect the SIWL, keep these measures in mind:
• Use suitable welding processes with low stress absorption (e.g. TIG welding).
• Make sure the material is correctly tempered before welding.
• Keep the weld under minimal mechanical loads and avoid excessive stress absorption.
• Check the material for cracks after welding and carry out heat treatment if necessary.