Designing Experiments to Affect Post Weld Heat Treatment Parameters: Using the Full Factorial Design in Inconel X-750 Welds

Abstract:

Alloy X-750 also has excellent properties down to cryogenic temperatures high stability and strength at high temperatures. This reason the alloy is used in manufacturing of gas turbine hot components. The research was study the effect of post weld heat treatment (PWHT) parameter on hardness and microstructure. The specimen was Inconel X-750 grade sheet of 2.8 mm thickness. This 2³ factorial design was used in experimental various post weld heat treatment at 705 and 845°C for 20 and 24 hour including solution temperature at 1,000 and 1,150°C. The welded specimens were tested by hardness testing in fusion zone (FZ) and heat affected zone (HAZ). The result showed that both of solution temperature, PWHT temperature and PWHT time interaction on hardness of FZ and HAZ at 95% confidential (P value < 0.05). The PWHT temperature and PWHT time interaction effect was the largest. The factor showed in the hardness increase with the low level (-1) of PWHT temperature and PWHT time for the hardness while it trended decrease for the solution temperature. The microstructure was the γ amount and small size would result in high hardness. Experimental results showed that the solution temperature at 1,150°C, PWHT temperature 705°C PWHT time of 20 hours provided intensity of gamma prime (γ) and MC carbide resulting in higher hardness both in FZ and HAZ.

• Periodical: Advanced Materials Research (Volume 711)
• Pages: 188-194
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.711.188
• Online since: June 2013
• Authors: Prachya Peasura, Bovornchok Poopat
• Keywords: Full Factorial Design (FFD), Hardness, Inconel X-750, Post Weld Heat Treatment

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