Corrosion Resistant Stainless Steel Wire, Annealed 0.15-12 mm

Corrosion resistance is usually discussed as a grade property, but on a finished part it is often a processing property. Cold drawing leaves residual tensile stress in the wire, and that stress is where chloride pitting and stress corrosion cracking start. Annealing after drawing is the step that removes it.

This wire is annealed and supplied bright or acid-pickled, from 0.15 mm to 12 mm, in 304, 304L and 316L. The low-carbon 304L and 316L variants are used where the part is welded, because the standard-carbon grades are more sensitive to chromium carbide precipitation in the 450-850 C range.

Surface condition is the second variable: oxide scale, embedded iron and drawing lubricant residue all interrupt the passive layer and become pitting initiation sites. Scale-free supply removes that risk before the part is formed.

Product Specifications

What Annealing Changes

Residual stress and cracking

A drawn wire carries tensile stress along its axis. In a chloride environment that stress drives stress corrosion cracking well below the load the part was designed for. Annealing relieves it, so the part fails only when the applied load exceeds the design figure.

Sensitisation at the weld

Standard 304 held in the 450-850 C range during welding can precipitate chromium carbides at the grain boundaries, which removes chromium from the adjacent metal. 304L and 316L keep carbon low enough to limit that effect, which is why they are specified for welded assemblies.

Surface and the passive layer

Scale, iron contamination and lubricant residue prevent the chromium oxide layer from forming evenly. Bright annealing in a reducing atmosphere or a controlled pickling step restores a clean surface before the part enters service.

Applications

Chemical and food processing equipment

Frames, baskets and support wire in 316L where washdown chemicals and chloride detergents are routine.

Water treatment and filtration

Filter cages, screen support and aeration frames, in sizes from 1.5 mm to 8 mm, where the wire stays wet and cannot be repainted.

Coastal and outdoor structures

Grilles, guards and ties exposed to salt air. Grade and surface both have to be right; 304 with a contaminated surface performs worse than 316L with a clean one.

Product Advantages

• Stress relieved after drawing - annealing reduces the residual tensile stress that drives stress corrosion cracking in chloride service.
• Low-carbon options where welded - 304L and 316L limit chromium carbide precipitation in the weld heat-affected zone.
• Clean surface supply - bright annealed or pickled, without embedded iron that would become a pitting site.
• Grade boundaries stated plainly - 304 for fresh water, indoor humidity and normal atmosphere; 316L where chlorides, salt air or chemical washdown are present.
• One diameter range - 0.15-12 mm covers filter cage wire and structural frame wire on the same specification.
• Traceable lots - heat number on every coil label, with mill test report 3.1 and surface contamination results on request.

Quality Control

Rod grade is confirmed by chemical or PMI check before drawing. Diameter is measured inline with end-of-coil sampling, tensile and elongation are tested per heat per ISO 6892-1, and the annealed surface is inspected for scale, stain and iron contamination. Coil build and packing are verified before dispatch.

Selection and Ordering Notes

1. State the corrosive medium: fresh water, salt air, chloride detergent or process chemical.
2. Confirm whether the part is welded, which decides between 304 and 304L or 316L.
3. Choose the surface: bright annealed for visible parts, pickled where a matte finish is acceptable.
4. Give the smallest bend radius and the diameter band for your forming process.
5. Provide sizes and annual volume for a tolerance and packing review.

Send the grade, diameter, corrosive medium and welding requirement for technical confirmation and quotation.