Complex of properties of 2219 alloy weld joint in T62 state under modeling operating conditions

Abstract

A complex of properties of aluminium alloy 2219 welded joint, made by single-pass welding with a non-fusible electrode along and across the rolled product, and heat-treated to the state T62, in liquid amyl and its vapors at a temperature of 50 °C for 45 days was investigated. Characteristics of plasticity and strength of 2219 alloy welded joints are as follows: in the longitudinal (D) direction – yield strength of the welded joint is (301–317) MPa, of the base metal (295—297) MPa, strength limit of the welded joint (409–415) MPa, of the base metal (422–425) MPa, elongation is (4.0–5.8)% and (17.6–19.1)%, respectively; in the transverse (P) direction – the yield strength of the welded joint is (309–331) MPa, of the base metal (304–307) MPa, the yield strength of the welded joint (392–414) MPa, of the base metal (428–433) MPa, elongation is (2.1–3.3)% and (12.6–15.0)%, respectively. The strength coefficient of welded joints in the longitudinal direction is 0.96, in the transverse – 0.94. Welded joints in the above environment are resistant to corrosion cracking and intergranular corrosion, resistance against exfoliating corrosion is evaluated by grade 2. Resistance of 2219 alloy in T62 state in amyl corresponds to the resistance group «stable», in amyl vapors – the group “highly resistant”. After aging in amyl and amyl vapors, the strength grades of the base metal samples and welded joints in both directions are almost unchanged, the plasticity parameters change ambiguously: the yield strength of the base metal increases by ~ (5–6)%, of welded joints decreases by ~ (6–7)%, the relative elongation of the base metal is reduced by ~ (5–16)%, of welded joints by about ~ 20 %. Independently of the direction of welding relative to metal’s rolling, samples’ fractures are mostly viscous. After the exposing in amyl, the coefficient of the strength of welded joints in the longitudinal and transverse directions is the same and equal to 0.91, after the influence of amyl vapors, it is 0.95 in the longitudinal direction and 0.96 in the transverse direction.