Intermediate Stress Relieving ISR: Where is it Required, Difference between DHT and ISR

Intermediate Stress Relieving ISR Heat treating a subassembly in a furnace to a specified cycle after critical constrained weld joint / joints have been completed without allowing the welds to cool below the pre-heat temperature. The rate of heating, soaking temperature, soaking time, and rate of cooling are all affected by the quality and thickness … Read more

Dehydrogenation Heat Treatment (DHT): Importance, Benefits, Cr-Mo-V Requirements

Dehydrogenation Heat Treatment (DHT) or Post-heating Dehydrogenation Heat Treatment (DHT) is a treatment utilised specifically when welding or preheat is paused or stopped during the fabrication cycle or PWHT is not done immediately due to further fabrication requirements. It is usually done at 300-350 °C [600 – 650˚F (min 570 ˚F)]. Very common and used … Read more

Preheating and Interpass Temperature: Importance, Benefits, Effects on Properties

Preheating Before beginning welding, heat the weldment to a minimum predetermined temperature and maintain it throughout the welding process is called preheating. Preheating is the process of elevating the temperature of the parent material on both sides of the joint to a temperature that is higher than ambient. Preheat is normally required by the relevant … Read more

Heat Treatment of welded joints: Reasons, Types of heat treatment in welded joints, bad or good ?

Heat Treatment of welded joints The intensity of the thermal cycles, which result in large residual stresses and/or weld metal and heat affected zone properties that differ radically from those of the parent material, determines the possibility of a weld defects. Failure might be sudden, occur over a short period of time, or present itself … Read more

Friction Stir Welding : Principle, Working, Equipment, Advantages, Applications

Friction Stir Welding According to AWS, “Friction stir welding (FSW) is a ‘solid state forge welding process’, is a type of friction welding which makes a weld joint between two workpieces by the heating and plastic material displacement caused by a rapidly rotating tool that traverses the weld joint”. In Friction stir welding, no filler … Read more

Which is better electrode polarity welding? Difference between DCEN, DCEP, AC

Effect of electrode polarity welding Due to difference in polarity in welding, bead shape is different for consumable and non-consumable welding process. Why?. the answer lies in physics of arc welding, about which you can know more here. but in short basic understanding point of view, the type of electron emission is different in both … Read more

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