Papers by Author: Kai Hua Zhang

Abstract: In Gleele-3500 Thermal Simulation Test Machine，conduct Thermal Simulation Experiment for High Niobium X80 Grade Pipeline Steel at Different Deformation Temperature, Deformation Extent and Coiling Temperature. Analysis the Microstructure Was Influenced by Different Rolling Process. According to the Thermal Simulation Experiments, Designed Test Scheme of Controlled Rolling and Controlled Cooling and Completed the Trial. the Results Showed that: for High Niobium X80 Grade Pipeline Steel, the Microstructures Are Acicular Ferrite and Have Good Mechanical Properties. the Low Temperature Impact Toughness Are More than 300J in -20°C and -40°C.

Abstract: In this paper, according to the problem of elongation unqualified in 560MPa grade sheet for automobile crossbeam in Pangang, through the microstructure detection、fracture observation and other methods to analysis the reason of elongation unqualified and propose process optimization measures. Used the measures, the elongation unqualified situation has obvious improvement in P560L, greatly improved qualified rate. The performance fluctuating range is small behind process optimization and have excellent forming properties and low temperature impact toughness. The users applied show that: products have excellent stamping performance, small rebound after stamping and stable quality. The various performances fully meet the used requirements of punch vertical frame in automobile.

Abstract: By adopting microalloying design, reasonable controlled rolling and cooling process, Pangang successful developed 600MPa grade hot rolled sheet for engineering mechanism. The average yield strength, tensile strength, elongation are 684MPa, 747MPa, 21.5%, respectively. The PQ600 steel which produced in Pangang with excellent forming property and welding property, can fully meet the requirements of users.

Abstract: In Gleele-3500 thermal simulation test machine, conduct thermal simulation experiment for high niobium X70 grade pipeline steel at different heating temperature, deformation temperature, deformation extent, cooling rate and coiling temperature. Analysis that the microstructure was influenced by different heating temperature and rolling process. The results showed that, For high niobium X70 grade pipeline steel, controlled heating temperature was1200±20°C, using HTP process, in large cooling rate range all can get the uniform acicular ferrite microstructures.

Abstract: In Formastor-Ⅱ thermal expansion phase transition instrument, determine test steel's thermal expansion curves with different cooling rates during continuous cooling. Using thermal expansion combined with metallographic-hardness method to draw the continuous cooling transformation curve (CCT).According to the test results draft thermal simulation program, in Gleele-3500 thermal simulation test machine, conduct thermal simulation experiment for vanadium microalloying X70 grade pipeline steel at different deformation temperature, deformation extent and coiling temperature. Analysis that the microstructure was influenced by different rolling process.The results showed that: in industrial production, the experiment steel's rough rolling temperature should be controlled more than 1020°C, finishing temperature controlled in 820±20°C and coiling temperature controlled in 500～530°C to obtain acicular ferrite.

Abstract: The continuous cooling transformation (CCT) behaviors of two vanadium (V) micro-alloyed steels with different Nitrogen (N) levels were investigated under the undeformed and deformed conditions, respectively. It is found that the austenite-bainite transformation is suppressed during dynamic CCT process due to hot deformation. For V-N steel, the transformation of austenite-proeutectoid ferrite and austenite-acicular ferrite (AF) occur under a wider range of cooling rates.