Experimental Study On Mechanical Properties Of High-Strength Steel BAR Applied In Railway Engineering

In order to cooperate with China’s railway industry strategy development for heavy haul railway and passenger dedicated line, and to promote the new brand of high-strength steel used in engineering, this paper mainly discussed experimental study on mechanical properties of high-strength steel base material applied in railway engineering with the support from China Railway Corporation scientific research test-"The Experimental Study on High-strength Steel Bar Applied in Railway Engineering". The main study works and achievements of this paper are summarized as follows:1、Systemic fatigue tests and relevant supporting experimental tests are conducted in high-strength steel bar, which totals 6 species including HRB400 with four reinforcement diameters (16,20,25 and 32mm) and HRBF400 with two reinforcement diameters(16 and 32mm),and stress ratio is 0.4.2、The experiment includes 6 treatments on holder section including setting thin aluminum tubes, setting thick aluminum tubes, setting thin steel tubes, winding iron wire, pasting high-strength glue and dealing with the ribs. By contrast, we choose the highest success rate of the holder section dealing with the ribs.3、"The Modified Chauvenet Criterion" suited for the single-point test method is proposed. Combined "the single-point test method", "the up and down methods" and "the double logarithmic bilinear model", tests and analyses for medium and long life fatigue S-N curve are structured.4、Based on test datas and "the double logarithmic bilinear model",constant amplitude fatigue performance test S-N curves of various test specifications materials for two stress ratios are obtained. It totals 6 S-N curves and 6 P-S-N curves.2 million,5 million and 10 million fatigue stress ranges for 6 species of high-strength steel base material are gained, and the relationship between them is discussed. Simultaneously, all the respective P-S-N curves and fatigue stress ranges having 97.7% reliability and 75% confidence are studied and acquired.5、Aimed at fatigue performance factors,such as the influence on HRB and HRBF and steel bar diameters, comparative analyses have been done. And a adaptability proposal of mechanical properties of high-strength steel bar is provided, which can provide a theoretical basis for the high-strength steel applied in railway bridges.