The Effect of Deep Cryogenic on Tensile Strength and Impact Toughness in Quench Tempered Steel Plate as a Candidate for Ballistic Resistance Material

Abstract

Ballistic resistant materials are materials containing right combination of hardness, strength, and toughness. The quench process produces high hardness and tensile strength but decreases toughness. The hardening process has been performed using an induction machine and a tempering process on a medium carbon steel plate. This work aimed to determine and analyze the effect of deep cryogenic treatment (DCT) on steel plates that have been quenched tempered. This research utilized steel plates of 130 x 130 x 8 mm size which has been quenched and then immersed in liquid nitrogen at a temperature of -196°C for 1, 5, 10, and 20 days. The micro Vickers hardness test specimen, tensile test and charpy impact test were made to determine the effect of immersion time. The test results and analysis showed that DCT had the ability to change microstructure, improve the hardness, tensile strength, and impact toughness. Furthermore, the maximum hardness was obtained during the immersion treatment of 20 days, which was 449.45 VHN and 1107.53 MPa, respectively. However, the highest toughness was obtained during the immersion of 10 days, which was 1,001 J/mm2. In order to get the optimal combination of ballistic characters, further ballistic testing is needed, both in simulation using the finite element method and ballistic experiment test.

Interface Structure in Friction Welded Joints between Stainless Steel 304 and Mild Carbon Steel

“…This study is a continuation of the previous study (Purwanto, Tauviqirrahman and Dzulfikar, 2021) to determine the bond occurring at the interface. Carbon steel and stainless steel with a length of 100 mm each with a cylindrical shape with a diameter of 10 mm were welded by the Continuous Drive Friction Welding (CFDW) method.…”

“…The interface is obvious as if both metals are not properly joined, but the tensile test shows a greater tensile strength of the joint than the tensile strength of the carbon steel base metal. From the tensile test results of all variables, all samples experience break in the carbon steel base metal (Purwanto, Tauviqirrahman and Dzulfikar, 2021). The interface structure of the joint at the midpoint (point 0) is shown in Figure 2.…”

“…Purwanto et al (Purwanto, Tauviqirrahman and Dzulfikar, 2021) had conducted a Continuous Drive Friction Welding (CFDW) study using a friction welding tool with 2000 rpm rotation on 304 stainless steel material, with mild carbon steel applying the pressure. Friction was done for 15 seconds and forging for 5 seconds, while the pressure is varied at 3 MPa, 4 MPa and 5 MPa.…”

“…Friction welding has been performed on carbon steel and stainless steel with pressure variations of 3 MPa, 4 MPa and 5 MPa. The tensile test results show a greater tensile strength of the joint than the strength of the base metal carbon steel and break occurred in the carbon steel base metal (Purwanto, Tauviqirrahman and Dzulfikar, 2021). In this study, a test was conducted to determine the interface structure occurring in the joint.…”