A Newly Developed High-Strength Martensitic Stainless Steel for the Sniper Rifle Barrel with High Shooting Accuracy

Abstract

With the increasing requirements for the shooting accuracy of the sniper rifle, a martensitic stainless steel 2Cr11Ni2Mo2WV (MPS700A) was developed by introducing Mo, W, and V into the currently used 2Cr13 steel. The 600 °C tensile tests showed that the ultimate tensile strength of MPS700A reached 767 MPa, the value was 46.4 % and 97.2 % higher than that of 2Cr13 and 30SiMn2MoV, respectively. Meanwhile, the -40 °C impact toughness of MPS700A was 20.5 % higher than that of 2Cr13 and comparable to 30SiMn2MoV. The intra-lath precipitation of ellipsoidal M2C nano carbides was observed in the MPS700A after tempering, which followed a Dyson orientation relationship (OR) of  with martensitic matrix. After deformation at 600 °C, such a Dyson OR was remained and the M2C in MPS700A exhibited higher thermal stability with respect to the M3C in 2Cr13, which hinders the dislocation movement and contributes to the higher strength of MPS700A at 600 °C. The fine martensitic lath as well as the homogeneously-dispersed M2C nano carbides also contributed to the higher impact toughness of MPS700A when compared with that of 2Cr13. Additionally, the salt spray test showed that the mass loss of MPS700A was 95.6% lower than that of Cr-plated 30SiMn2MoV and comparable to that of 2Cr13. Based on above analysis, the MPS700A exhibits high strength up to 600 °C, excellent impact toughness at low temperature and prominent corrosion resistance, making the MPS700A as a promising gun barrel material for the sniper rifle with long lifespan and high shooting accuracy.

Keywords: Martensitic stainless steel, elevated-temperature strength, corrosion, Wear, sniper rifle barrel