Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Titanium alloy argon welding workshop overall design and principle verification
Weihua Chen1,2, Wentian Zou2, Keke Ge2, Meng Xu2, Jia Zhou2, Aifeng Zhang2*, Hong Yi1*
1.

2.

State Key Lab of Ocean Engineering, Shanghai Jiao Tong University.
Shanghai, China.
State Key Laboratory of Deep-sea Manned Submersible, China Ship Scientific Research Center.
Wuxi, Jiangsu, China.

ABSTRACTThe pressure shell material of large-depth manned equipment is mainly
titanium alloy, with large volume, various welding joints and great
difficulty in construction. The welding workload accounts for more than
40% of the total construction workload. The welding environment iscomplicated, and the temperature and humidity are greatlydifferent. Titanium has strong chemical activity and is sensitive toimpurities and water. It is easily polluted by air, water, grease and oxide
scale during welding, leading to impurities such as oxygen, hydrogen,nitrogen and carbon dissolved in the weld, thus deteriorating the joint
performance (Li DD et al., 2003). In order to avoid material
contamination, the whole welding process needs to be separated from thesteel operation area and carried out in an independent clean workshop(Jia HT et al., 2020). The working environment temperature is not lessthan 5℃, the relative humidity is not more than 80%, the wind speed atconstruction site is not more than 1.5m/s. Different from steel, repairing
times of titanium alloy weld at the same position should not exceed twotimes, which requires higher quality of weld. At present, mature welding
methods for titanium alloy are mainly GTAW and ELECTRON beam
welding, but the protective effect of GTAW is limited and electron beam
welding is limited by vacuum chamber (Chen FL, 2019). GTAW
technology in high concentration argon gas environment does not needhigh vacuum chamber and overcomes the shortcoming of traditional
GTAW welding seam protection. Therefore, the construction oftitanium alloy argon welding workshop can provide an ideal weldingenvironment for the integral welding of titanium alloy pressure-resistant
structure of underwater manned equipment.

Titanium alloy is the main material of pressure-resistant shell of
underwater submarine. Although the design and manufacturing
technology of spherical pressure-resistant structure of manned
submersibles has matured, the domestic large-scale ring rib shellprocessing and construction technology is not mature enough, especiallythe titanium alloy welding technology. The high concentration argon
welding workshop designed in this paper is mainly aimed at the overallwelding of the typical titanium alloy large ring ribbed column shell, andthe key technology is verified by the principle prototype. Finally, themechanical properties of welding samples are evaluated.

KEY WORDS: Argon welding workshop; Titanium alloy; Overalldesign; Construction process; Principle prototype.

INTRODUCTION
Titanium alloy is mostly used as the pressure-resistant shell material oflarge-depth manned equipment. The design, processing and construction
technology of spherical pressure-resistant structure of manned
submersible is approaching maturity, while the processing andconstruction technology of large ring-ribbed cylindrical shell in China is
not perfect, especially the titanium alloy welding technology (SOHUnews, 2021). Due to the large size of the pressure-resistant structure andthe large thick thickness of the plate and shell, the existing technology oflarge-depth manned equipment cannot achieve integrated forming, andthe forming of pressure-resistant cylindrical shell, ribs and hemisphericsealing head unit structures all need welding. Welding technology is oneof the core technologies in the manufacturing process of titanium alloypressure shell. The maturity and perfection of titanium alloy welding
technology directly affects the safety and reliability of titanium alloypressure shell of manned equipment.

DEVELOPMENT STATUS
At present, Russia is the main country that owns titanium alloy
submarine (Zhang TH, 2021). This paper mainly investigates the data of
Russian titanium alloy argon welding workshop, focusing on welding oftitanium alloy parts of nuclear submarine and aircraft engine. There isno large argon sealed workshop for titanium alloy welding in China.

DEMAND ANALYSIS

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