Effects of Heat Treatment on the Microstructure and Mechanical Properties of a Novel H-Grade Sucker Rod Steel

Abstract

The sucker rod is an extremely important equipment in oil exploitation, but with the deepening and harsh environment of the petroleum well, higher requirements are put forward for the strength and corrosion resistance of the sucker rod. The most commonly used steel for H grade sucker rods is 4330 steel. However, it has characteristics such as high cost and relatively low sulfide stress cracking resistance. Thus, a novel sucker rod steel with a composition of 0.2 wt.% Cu and 1.2 wt.% Ni was designed. Normalizing + tempering (NT) and quenching + tempering (QT) heat treatment were optimized to render the mechanical properties of the novel sucker rod steel to reach the H grade. Additionally, effects of heat treatment on the microstructural evolution and mechanical properties of the novel sucker rod steel were investigated by optical microscope, scanning electron microscope and mechanical property tests. The results showed that the microstructure is tempered sorbite and the mechanical properties reach H grade after NT and QT. Specifically, the tensile strength, yield strength, elongation and impact toughness of NT/QT samples reached 1010.58/1124.37 MPa, 875.93/1042.63 MPa, 15.66/11.59% and ~77.48/~111.69 J/cm2, respectively. Furthermore, the finer and more dispersed carbides were observed in the QT sample, which means that the QT sample had better strength and toughness.

Change in Hydrogen Trapping Characteristics and Influence on Hydrogen Embrittlement Sensitivity in a Medium-Carbon, High-Strength Steel: The Effects of Heat Treatments

“…Adjusting the microstructure through a heat treatment process is a common way through which to improve the hydrogen embrittlement resistance of steel. N&T or Q&T are the two most common heat treatment processes, and they are widely used to control the microstructure of steel due to their ease of operation and low cost [23]. Imdad et al [24] studied the HE sensitivity of 42CrMo4 steel after conducting annealed, normalized, quenched, and tempered heat treatments.…”

Fatigue Behaviour of Tempered and Isothermal Heat Treated Aisi 5160 Leaf Spring Steel

“…Only a few technical applications call for quenched steel. Temperatures may be adjusted to gradually reduce hardness while increasing ductility and impact strength [1]. Temper treatment considerably influences the mechanical characteristics of a selected alloy.…”

Effect of High Magnetic Field in Combination with High-Temperature Tempering on Microstructures and Mechanical Properties of GCr15 Bearing Steel

“…The tempering and quenching (Q&P) process can effectively improve the size and distribution of carbides [6][7][8] and is an important method to adjust the microstructures and properties of steels [7,9]. During the high-temperature tempering of steels, the TS structures can be obtained [8,10], with a uniform distribution of finer carbides [6,8], providing the most effective pinning at sub-grain boundaries [11], which is conducive to the improvement of the fatigue life [12].…”