Welded Joints In Titanium Alloys Research Articles

Statistical analysis of tensile strength and elongation of pulse TIG welded titanium alloy joints using Weibull distribution

Abstract In this study, the tensile strength of a pulsed current tungsten inert gas welded Ti-6Al-4 V plate has been statistically analysed by Weibull distribution. Titanium alloy of 1.6 mm thickness was welded with pulsed current tungsten inert gas welding. Testing of mechanical properties was done to understand the influence of pulsing current on the fabricated joint. But the result obtained has to be consistent and repeatable. Hence, this paper investigates a method for predicting the reliability of values obtained for tensile strength and elongation with consistency. The tensile strength results obtained vary between 975 and 1160 MPa and percentage elongation vary between 2.4 and 5.9%. Using Weibull technique in conjunction with the experimental data, we can predict the output more accurately. Using Weibull distribution, the welded joint reliability can be obtained. The probability distribution according to which the joint will fail is estimated with the help of Weibull analysis.

Effect of welding methods on the structure and mechanical properties of welded joints in creep-resisting titanium alloys with different initial structural conditions

Problems of welding rotor components made of creep-resisting titanium alloys are investigated. Comparative tests of the effects of fusion welding and rotational friction welding (FW) on the structure and properties of welded joints in titanium alloys are carried out. The experimental results show that welded joints produced by rotational FW have a structure identical to the structure of the parent metal, and the heat-affected zone does not form at all. The optimum conditions of FW of creep-resisting titanium alloys are determined. Irrespective of the initial type of structure, these conditions result in the mechanical properties of the welded joint at a level of 0.9 of the properties of the parent metal.

Reconditioning rotor components of gas turbine engines produced from titanium alloys by welding using modified submicrocrystalline filler materials

Experimental results show that the application of standard methods of reconditioning components of titanium alloys reduces the mechanical properties of welded joints by up to 30%. The main reasons for this are structural changes and weld defects. The modified (La, Y and B) filler materials were developed from titanium alloys with a submicrocrystalline structure. These materials produce the equiaxed and ductile structures in welded joints in titanium alloys so that the mechanical properties of the welded joints equal 0.9 of the properties of the parent metal. Consequently, the range of repairs of rotors of gas turbine engines can be greatly widened.

Heat and thermomechanical treatment and textural hardening of weldable titanium alloys

The theoretical and practical principles of heat, thermomechanical treatment and textural hardening of weldable titanium alloys are described. The results of investigations of the effect of deformation and heat treatment on the mechanical properties of welded joints in titanium alloys are presented.

Effect of welding conditions on the impact toughness of welded joints in titanium alloys

Effect of the welding conditions and annealing on the impact strength of different heat-affected areas of the titanium welded joints is studied. Maximum impact strength is established in the range of 350–550°C, in practice this coincides with the temperature peaks for short-time strength and fatigue life.

Effect of Size and Location of a Weld Defect on Fatigue Life for Argon-Arc Welded Titanium Alloy Joint

Analytical studies were made on effect of size and location of a weld defect on fatigue life for argon-arc welded titanium alloy joint. In the analyses, a weld defect was assumed as an initial crack, and the crack growth life was taken as total fatigue life. By using the Isida and Noguchi’s stress intensity factor solution for a plate containing an embedded elliptical subsurface crack under tension, the life prediction code FASTRAN3.9 was revised. A small crack methodology based on the plasticity-induced crack-closure concept and the effective stress intensity factor range, Keff , was used to predict the total fatigue life of welded joint, and to study the effect of the size and location of weld defect on fatigue life by means of the revised FASTRAN3.9 code. Limited amounts of experimental data were used to make comparison with the predictions. The predicted fatigue lives are in reasonable agreement with experiments, and the effect of both the size and location of the weld defect on fatigue life was found to be significant.

Structure and internal-stress formation in VT20 titanium-alloy welded joints

Microstructure, texture, and microhardness and residual-stress distributions are studied in a VT20 alloy welded shell consisting of two coaxial nested components connected by a circular weld.

Fatigue Behavior and Life Prediction for Argon-Arc Weld Joints Based on Small Crack Methodology

Experimental and analytical studies were made on the fatigue behavior and life prediction for argon-arc welded titanium alloy joints, TA15. High cycle fatigue tests at two stress ratios, R=0.5 and 0.06, were carried out on smooth specimens with the argon-arc weld joint located at the specimen center section. Through macroscopic observation and SEM fractographic analysis, it was found that most of the cracks were initiated at weld defects such as voids and inclusions at the edge of weld and in the heat affected zone (HAZ). A small crack methodology based on the plasticity-induced crack-closure concept and the effective stress intensity factor range, ΔKeff , was used to predict the total fatigue life of the weld joints. Large crack growth curve for cracks in the HAZ area was employed as the da/dN-ΔKeff base-line of the TA15 alloy. From fractographic measurements, an average defect size of 100 microns was assumed as the initial small crack size in the life predictions. Predicted total fatigue life by solely considering small crack growth stage agreed well with the experimental data.

Reducing porosity in thin‐sheet welded joints in titanium alloys

Reducing porosity in thin‐sheet welded joints in titanium alloys

Electron beam welding and zone heat treatment of welded joints in titanium alloys and high‐strength steels

Electron beam welding and zone heat treatment of welded joints in titanium alloys and high‐strength steels

Reduction of residual stresses in welded joints in titanium alloys

Reduction of residual stresses in welded joints in titanium alloys

Effect of structural heterogeneity on the corrosion resistance of welded joints in titanium alloys

(1990). Effect of structural heterogeneity on the corrosion resistance of welded joints in titanium alloys. Welding International: Vol. 4, No. 1, pp. 5-10.

Dendritic liquation in the weld metal of welded joints in titanium alloys

Dendritic liquation in the weld metal of welded joints in titanium alloys

Special features of the transition region between the heat affected zone and parent metal in welded joints in titanium alloys

Special features of the transition region between the heat affected zone and parent metal in welded joints in titanium alloys

The mechanical properties of welded joints of titanium alloys with an elevated oxygen content

It was found in [3, 4] that the p r o p e r t i e s of the weld s e a m s in t i tan ium al loys can be i m p r o v e d by l imi t ing the concen t r a t i ons of i m p u r i t i e s , p a r t i c u l a r l y oxygen. However , the r e s u l t s in [5, 6] lead to the conc lus ion that the effect of oxygen on the duct i l i ty of the weld s e a m in t i t an ium a l loys will differ in r e l a t ion to the combina t ion of a l loying e l emen t s in t i t an ium.