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Title: Joining techniques for a reduced activation 12Cr steel for inertial fusion energy

At Lawrence Livermore National Laboratory, we are developing a reduced activation ferritic martensitic steel that is based on the ferritic martensitic steel HT-9. As a part of the development of this steel, we tested a series of welding processes for characterization, including conventional welds (electron beam, tungsten inert gas, and laser) as well as solid-state welds (hot isostatic pressing). We also heat treated the joints at various temperatures between 750 °C and 1050 °C to find a suitable normalization scheme. The modified HT-9 reduced activation ferritic martensitic steel appears highly suitable to welding and diffusion bonding. All welds showed good quality fusion zones with insignificant cracking or porosity. Additionally, a heat treatment schedule of 950 °C for one hour caused minimal grain growth while still converging the hardness of the base metal with that of the fusion and heat-affected zones. Also, modified HT-9 diffusion bonds that were created at temperatures of at least 950 °C for two hours at 103 MPa had interface tensile strengths of greater than 600 MPa. The diffusion bonds showed no evidence of increased hardness nor void formation at the diffusion bonded interface.
Authors:
 [1] ;  [1] ;  [1] ; ORCiD logo [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
OSTI Identifier:
1165758
DOE Contract Number:
DE-AC52-07NA27344
Resource Type:
Journal Article
Resource Relation:
Journal Name: Fusion Engineering and Design; Journal Volume: 89; Journal Issue: 7-8
Publisher:
Elsevier
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 36 MATERIALS SCIENCE; 22 GENERAL STUDIES OF NUCLEAR REACTORS; 29 ENERGY PLANNING, POLICY AND ECONOMY RAFM STEEL; DIFFUSION BONDING; HIP; WELDING