CTOD fracture toughness test has been used by a large number of domestic welding workers to assess weld safety. During the construction of offshore oil platform, Offshore Oil Engineering Co., Ltd. applied CTOD fracture toughness test to evaluate the low temperature fracture toughness of welds. The test results showed that the fracture toughness values of most samples at low temperature are qualified for EH36 steel welding joints and heat affected zones with three welding techniques, namely, shielded metal arc welding, single wire submerged arc welding and double wire submerged arc welding without post weld heat treatment, The evaluation of welded joints can be used without post weld heat treatment to shorten the manufacturing cycle of offshore platform structures and reduce manufacturing costs. The whole test work has been well received by Philips Oil Company and DNV Det Norske Veritas.

Analysis of Application Scope of Rotary Spherical Compensator in Overhead Pipeline
Rotary spherical compensator can be widely used in metallurgy, petroleum, chemical industry, electric power, light industry, textile, construction, national defense establishment and other industries. It has the following uses:
1. It is used in thermal pipelines to compensate for thermal shrinkage, and its compensation ability is 5-10 times of that of the compensator.
2. It is used as a universal joint in the vaporization cooling system of metallurgical equipment (such as blast furnace, converter, electric furnace, heating furnace, etc.).
3. It is used in various pipelines of buildings to avoid damage to pipelines due to unpredictable reasons such as uneven settlement of foundation or vibration.
The stress analysis of the sleeve type compensator and the fixed support of the rotary type compensator of the overhead pipeline installation is carried out.