Electrical Pre-Heat and PWHT of piping

On-site electrical heat treatment services include the following:

Welding Preheat.

Post Weld Heat Treatment – PWHT.

Hydrogen Bake Out.

Line Thaws.

Refractory Dry-out’s.

Phenolic Cures.

Coating Cures.

Heat/Shrink Expansion.

Permanent and Temporary Furnaces

Warming Systems.

OEM Equipment Manufacturing.

Calibration & Service.

THE BENEFITS OF PRE-HEAT TREATMENT:

Reduces the levels of thermal stress.

Compensates for high heat loss.

Minimizes the rate of weld hardening.

Reduces the porosity of the weld.

Reduces hydrogen cracking.

Improves micro-structure of heat-affected zones.

Benefits of Weld Preheating and Reducing Thermal Stress:

PROBLEM:

Thermal Stresses Occur as Molten Weld Pools Cool

Cracking Can Occur Both During and After Welding

Colder Parent Metal Resists the Inevitable Contraction of the Weld Metal

SOLUTION:

Preheating reduces the temperature difference between the Weld Metal and the Parent Metal and Minimizes Potential Cracking Pre Weld Heat Treating and High heat Loss

PROBLEM:

Heavy Wall Materials and Aluminum Alloys with higher thermal conductivity can act as a heat sink, drawing heat away from a weld and cooling at an accelerated rate.

SOLUTION:

Preheat Heat treatment will reduce the cooling rate of the deposited weld material and allow a proper fusion with the parent metal Pre Weld Heat Treatment will Reduce Weld Porosity

PROBLEM:

If moisture is present at a welded joint, the high heat of the welding arc will break the water down into its elements, hydrogen and oxygen. The hydrogen by-product easily dissolves into the weld metal and causes weld porosity during weld solidification.

SOLUTION:

Performing a pre-weld heat treat drives away moisture from the welded joint. Pre Weld Heat Treatment will Reduce Weld Hardening

PROBLEM:

During and after completing of the welding process, both the weld pool and the Heat Affected Zone (HAZ) can harden and crack when cooling at a rapid pace

SOLUTION:

By preheating the weld and the Heat Affected Zone (HAZ) the rate of cooling can be controlled and reduced thereby eliminating problems associated with weld hardening Pre Weld Heat Treating Prevent Hydrogen Cracking

PROBLEM:

Electrode Coatings and Fluxes can often introduce moisture directly to the arc and weld pool. The increase in moistures increases the possibility of weld or Heat Affected Zone (HAZ) cracking.

SOLUTION:

Preheating slows down the weld cooling rate which allows hydrogen to escape Pre Weld Heating Improves Material Microstructure

PROBLEM:

Low Alloy Steels containing elements such as chromium, nickel, molybdenum, and vanadium are susceptible to cracking in the Heat Affected Zone (HAZ)

SOLUTION:

Preheating improves the microstructure inside the HAZ by reducing the post-weld cooling rate. The reduced cooling rate produces: o A more desirable and ductile microstructure to be formed o Minimizes Under Surface Cracking

→Post Weld Heat Treatment Services