Comparison of Oscillography Impact Properties between a New Type Drilling Collar Steel and 4145H

摘要

Average impact energy of 4145H steel and X new type drilling collar steel satisfied the standard of "SYT5144-2007 Drilling collar" and "API SPEC7". With temperature getting down, impact energy of 4145H steel decreased, impact energy Cof X drilling collar steel is a lot higher than 4145H steel, crack propagation energy and crack propagation energy/impact energy ratio decreased. Lower temperature leads to higher crack propagation rate. The crack propagation energy of 4145H is lower than X drilling collar steel. The crack propagation energy/impact energy ratios of X drilling collar steel are at least 3% higher than 4145H for different temperature. In drilling, crack growth rate in X DC was slower than 4145H DC, crack growth rate was fast, and the DC was easy to fracture in low temperature In China, 4145H drilling collar (DC) steel, the international DC steel recommend by AISI, has been widely applied in all oil field [1]. 4145H DC failure occurs frequently, fracture failure is one of the most serious accidents in drilling process and lead to massive economic loss [2]. Oscillography impact tests of specimens which were longitudinal sampled in 4145H and X new type DC steel were tested in different temperatures. Oscillography impact properties of 4145H and X DC steel in different temperatures were analyzed. These data offers basic experimental evidence to the analysis of 4145H DC fracture mechanism and offer experimental basis to develop new type DC steel.