304Cu Cold Heading Wire - Forming Without Magnetism
304Cu cold heading wire
,non-magnetic stainless steel wire
,cold heading wire without magnetism
304Cu Cold Heading Wire - Forming Without Magnetism
Product Introduction
TOPONE supplies 304Cu stainless steel cold heading wire in 0.15-12 mm diameters for fasteners and small parts that are formed deep and must stay essentially non-magnetic. The copper addition stabilizes the austenite, so the heavy plastic deformation of cold heading produces far less strain-induced martensite than standard 304. Soft annealed condition, 3.1 MTC with every lot.
Product Specifications
| Parameter | Specification |
|---|---|
| Grade | 304Cu (about 18Cr-8Ni-2Cu, UNS S30430 type) |
| Diameter range | 0.15-12 mm |
| Condition | soft annealed for cold heading |
| Magnetism after forming | markedly lower than standard 304 |
| Cold workability | high reduction without cracking |
| Surface | soap coated or bright drawn |
| Delivery | coil or spool, 3.1 MTC per lot |
Why Copper Changes the Game
Cold heading deforms the wire head far beyond its yield point. In standard 304, that deformation converts part of the austenite to martensite, which is magnetic - many a polished fastener has surprised a customer with a magnet. Copper suppresses this transformation: the austenite stays stable, so 304Cu parts remain weakly magnetic at most, even after severe heading. The same stability is what lets the steel take large cold reductions without edge cracking.
Choosing Between 304 and 304Cu
- Fasteners sold as non-magnetic or low-magnetic: 304Cu is the straightforward answer.
- Deep heads, six-lobe sockets and complex cold forms: the extra formability of 304Cu reduces die wear and splitting.
- Plain structural bolts where magnetism is irrelevant: standard 304 remains the economical choice.
- Parts that must remain non-magnetic after tapping or threading: verify with a sample; threading adds deformation too.
Wire Preparation for Heading
Wire arrives annealed and surface conditioned for feeding. Diameter is held to heading tolerance along the coil so the die fill repeats, and the soap film carries the wire through the die without galling. Draw or re-anneal schedules can be matched to your heading sequence on request.
Applications
- Precision screws and bolts for electronics
- Optical and instrument fasteners
- Rivets and contact parts formed cold
- Small deep-formed components
Product Advantages
- Low residual magnetism even after heavy heading
- High cold reducibility - fewer splits, longer die life
- Tight diameter tolerance for repeatable die fill
- 3.1 MTC with chemistry including copper content per heat
Quality Control
Chemistry is verified per heat, mechanical properties per lot. Magnetic permeability can be checked on formed sample parts and reported with the shipment on request.
Selection and Ordering Notes
- Give the wire diameter and the heading reduction planned.
- State any magnetism limit your customer applies.
- Choose soap coated or bright surface.
- Confirm coil weight and spool type.
- Request sample heading trials when starting a new part.
