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Welding stainless steels and nickel alloys is all about cleanliness and choosing the right filler metal. These guidelines are intended as a step-by-step aid to the successful welding of stainless steels and nickel alloys.

Step 1: Selection of Filler Metal Alloy for Welding ProcessWhen both base metals are the same, use the base metal alloy as a guide. For example, if joining 316L to 316L, use 316L filler metal. Past experience may show preferential corrosion in the weld, in which case, moving up in alloy content may be required. Careful consideration regarding how far to move up is necessary, so as not to over-alloy causing galvanic corrosion.

For dissimilar joint welding (example; Stainless ...

Basicity is commonly used to describe the metallurgical behavior of a welding flux. The basicity index is a ratio between basic and acid compounds (oxides and fluorides) of which the flux is composed.

There are several ways of calculating basicity and in welding Boniszewski's formula has become the predominant way of calculating basicity.

Welding fluxes can be divided into three groups:  Type of welding flux   Basicity   Acid fluxes   <0.9   Neutral fluxes   0.9 - 1.2   Basic fluxes   >1.2 Basicity ...

Problem Cause Solution Cracking centerline Excessive dilution Add more filler metal or use technique to achieve slightly convex weld bead. Check dissimiliar joining chart to make sure correct filler material is being used. Cracking Random Overstressed weld Lower amperage or voltage or increase travel speed to lower heat input, which causes distortion. Use step welding technique, change joint design. Keep the interpass temperature below 150°C (300°F). Cracking HAZ Usually base metal related Ensure not welding with machinable grade of material containing high levels of low melting intermetallics. Porosity Poor gas ...

Shielding the Weld The primary tasks of a shielding gas are to protect the weld pool from the influence of the atmosphere, i.e. from oxidation and nitrogen absorption, and to stabilize the electric arc. The choice of shielding gas can also influence the characteristics of the weld penetration profile.

Shielding Gas Protection Shielding gases for MIG/GMAW welding

The basic gas for MIG/MAG welding is argon (Ar). Helium (He) can be added to increase penetration and fluidity of the weld pool. Argon or argon/helium mixtures can be used for welding all grades. However, small additions of oxygen (O2) or carbon dioxide (CO2) are usually needed to stabilize the arc, improve the fluidity and ...

By carefully selecting raw materials and optimizing manufacturing conditions the Exaton fluxes have guaranteed as-delivered moisture content from the factory.

Normally, the fluxes are delivered in steel drums, each containing 25 kg (55 lbs). Each pallet has a net weight of 500–1000 kg (1100–2200 lbs) and is shrink wrapped in plastic or packed in wooden crates before delivery from the factory.

To maintain the as-delivered moisture content, as long as possible, the handling and storage of the flux must be done according to the following requirements.

Transport

Transportation of the flux must be done in covered vehicles.

Unbroken pallets must be shrink wrapped in plastic or kept ...