Development process of T91 high pressure boiler tube
The chemical composition of the T91 high-pressure boiler tube : to obtain the best comprehensive performance for T91, it is necessary to optimize the chemical composition, especially to control the content of five harmful elements and hydrogen and oxygen. The material composition of Honggang has been stable.

Production process of T91 high-pressure boiler tube : high-pressure boiler tube blank production process: high-quality scrap steel + pig iron EAT (100t VHP) + induction furnace LFVD continuous casting and rolling annealing skin magnetic particle inspection. High-pressure boiler control tube production process: tube billet heating centering piercing tube micro-sheet heat treatment cold rolling (pull) normalizing + tempering finishing ultrasonic + eddy current flaw detection spectral analysis identification + packaging storage.

T91 high pressure boiler tube heat treatment process system ASME SA-213 standard stipulates that T91 heat treatment system is normalized + tempered, normalizing temperature ≥ 1040 ° C, tempering temperature ≥ 730 ° C.

Test results and analysis of steel tubes of T91 high-pressure boiler tubes . The sample tubes (∮51×8) were tested for size. The detection method is as follows: the sample tube is tested at two places (No. 1 and No. 2), and the wall thickness is measured at a position of 45° in the circumferential direction for a total of eight points; the outer diameter is every 45° in the circumferential direction. Position measurement, a total of 4 values. The wall thickness and outer diameter are far superior to the GB5310 standard.

The high temperature mechanical properties test was carried out at 575 ° C, 600 ° C, and 625 ° C according to the GB5310 standard. The test results of high temperature short-term mechanical properties show that the short-term high-temperature mechanical properties are good, and the strength fully meets the requirements of 10Cr9Mo1VNbN in GB5310 standard.

Process performance test: According to the SA-450 standard, the sampling tube (∮51×8) is required for the flattening test. The flattening height is calculated: 36mm. No cracks or cracks are visible after the test. The test results show that the requirements are fully met. The -450 standard requires that the sampling tube (∮51×8) be used for the flare test. The angle of the top core of the flare test is 60°, and the expansion ratio of the inner diameter of the sample after flaring is 19%. No cracks or cracks were observed, and the test results showed that the requirements were fully met.