Daido Bunseki Research Inc.

Chemical Composition & Environmental Analysis
Structural Analysis/Shape Observation
Physical Property Measurement
Fracture, fatigue, and degradation
Foreign matter, discoloration, surface property
Corrosion, corrosion prevention
Analysis Examples
Fracture, fatigue, and degradation
Analysis & Testing Examples: Investigation into cause of defect: J-03--Examination of SUS316 heating pipe plate damage--
 --Examination example of SUS316 heating pipe plate damage in the heat exchanger part of electric furnace dust reduction equipment--
1. Cracking which appears near the pipe plate weld bead
 Microstructures which are typical of transgranular stress corrosion cracking were observed.
Cracking which appears near the pipe plate weld bead

2. SEM photos of fractured surface
 The crack origin was recognized as intergranular stress corrosion cracking starting from pitting, and quasi-cleavage type cracking was observed on the fractured surface, it was a result of transgranular stress corrosion cracking.
Near crack origin   Crack propagation portion
Near crack origin   Crack propagation portion

3. Analysis of adhered dust and estimation of used environment

 From the wet chemical components of the adhered dust, 15% was determined as chlorine content, while 8 to 9% was determined as moisture content.
 The air intake area showed the most prevalent cracking, with no cracking generated in high temperature portion.
4. Measures
 When using SUS316, stress relief annealing is needed to reduce the residual stress.
 The surface temperature is considered low when between 100 and 150 ℃, so ferritic stainless steel may be adopted for use.
Daido Bunseki Research, Inc. 2-30 Daido-cho, Minami-ku, Nagoya 457-8545 Phone: 052-611-9434 Fax: 052-611-9948