302 Spring Wire - JIS EN ASTM Grade Equivalence
302 stainless spring wire
,JIS EN ASTM grade 302 wire
,302 spring wire grade equivalence
302 Spring Wire - JIS EN ASTM Grade Equivalence
Three standards describe the same material in three different ways. A Japanese drawing calls for SUS302-WPB, a European drawing calls for 1.4310 in the DH condition, an American drawing calls for 302 spring temper to ASTM A313. They are all austenitic chromium nickel spring wire, and they are not interchangeable without checking the grade classification, the tensile range and the test requirements behind each designation. This page sets out how each system groups its grades, where the classifications line up, and what has to be confirmed before one is substituted for another.
Product Specifications
| Item | Specification |
|---|---|
| Product Name | 302 Stainless Steel Spring Wire |
| Material | AISI 302 / SUS302 / 1.4310 / UNS S30200 |
| Diameter Range | 0.15-12 mm |
| Diameter Tolerance | ±0.01 mm (fine wire), ±0.02 mm (0.5-3 mm), ±0.03 mm (above 3 mm) |
| Tensile Strength | 1400-1800 MPa, spring temper (size dependent) |
| Delivery Condition | Cold drawn spring temper, bright |
| Surface | Bright drawn, soap coated on request |
| Coil Weight | 1-100 kg |
| Reference Standards | JIS G 4314, EN 10270-3, ASTM A313, GB/T 24588 |
How Each System Groups Its Grades
JIS G 4314
The Japanese standard separates grades by intended duty within the same steel type, using class suffixes under the material designation. The practical consequence is that the class letter, not only the SUS number, carries the strength requirement. A drawing that says SUS302 without a class has not finished specifying the wire, and the supplier has to ask which class applies before quoting.
EN 10270-3
The European standard groups by loading condition rather than by steel type: one class for static applications, two for dynamic applications at different stress levels, and one explicitly not intended for springs. This is the most useful of the three for a designer, because the class tells you the intended duty directly. Substituting a static class for a dynamic one on the same part is the most common equivalence error in Europe.
ASTM A313
The American standard lists grades and conditions, and leaves much of the mechanical requirement to be agreed between purchaser and supplier within the range the standard allows. A certificate saying 302 to A313 is therefore less specific than a European class designation. When comparing a US and a European offer, the tensile range has to be compared directly rather than inferred from the designation.
Where the Classifications Line Up
Same Steel, Different Labels
302, SUS302, 1.4310 and UNS S30200 describe the same nominal composition: around 17% chromium, 8% nickel, with the carbon held low and silicon controlled for spring drawing. Composition equivalence is the easy part. The 1.4310 designation adds a letter suffix for the condition, and the JIS designation adds a class suffix for the duty, so a full comparison needs all three elements: steel, condition and class.
Where They Diverge
The tensile ranges behind equivalent-sounding classes are not identical, and neither are the sampling requirements. A grade that meets the minimum of one standard may sit below the minimum of another at the same diameter. The divergence widens at small diameters, where all three systems set higher strength requirements but not at the same rate.
Making an Equivalence Claim Safely
Compare Three Things, Not One
Compare the composition, the tensile range at the actual diameter, and the test requirements. If all three match or the offered wire is on the stronger side with adequate elongation, the substitution is defensible. If the tensile range overlaps only partially, the part design has to be checked against the lower bound of the offered wire, not against its typical value.
Document It
Write the comparison into the purchase order: the source standard and class, the offered standard and class, and the tensile range at the ordered diameter. This protects both sides if a customer later questions the substitution, and it makes the next repeat order unambiguous.
Applications
Sourcing Against a Japanese Drawing
Japanese spring drawings are common in automotive and appliance supply chains, and they usually specify both the SUS number and the class. Where the class is missing, confirm it with the customer rather than choosing the higher one, since a stronger wire may fail the forming operation even though it passes the load requirement.
Dual Standard Projects
Equipment built for a European customer and serviced in Asia often carries both designations on the same bill of materials. Supplying one wire that satisfies both is usually possible in 302, provided the tensile range is stated explicitly and the test methods are the stricter of the two.
Replacing an Obsolete Specification
Older drawings sometimes reference withdrawn editions. Rather than matching the edition number, match the mechanical requirement at the diameter and confirm it against the current edition of the same standard, which is what an auditor will check.
Product Advantages
- Single wire grade documented against JIS, EN and ASTM at once, simplifying equivalence claims in the purchase order.
- Tensile range stated for the actual ordered diameter, since all three standards vary strength with size.
- Test results reported per lot with the method named, so they can be compared with whichever standard the customer audits against.
- Diameter tolerance of ±0.01 mm on fine sizes, matching the tighter requirement in the three systems.
- Composition confirmed per heat, supporting the 302 / SUS302 / 1.4310 equivalence in writing.
Quality Control
Each heat is checked for composition against the 302 specification before drawing. Tensile strength, elongation, diameter and surface are tested per lot, and results are reported against the heat number. Where a customer order references more than one standard, the test plan is set to the stricter requirement of the two so that one set of results satisfies both.
Selection and Ordering Notes
- Quote the steel designation and the class or condition together: SUS302 with class, 1.4310 with suffix, or 302 with temper.
- State the tensile range required at the ordered diameter rather than referring to a standard minimum alone.
- Name every standard the delivery has to satisfy, and state which one governs if their requirements conflict.
- Confirm the test methods and sampling frequency, as these differ more between the three systems than the compositions do.
- Keep the equivalence note on file with the order, so that a later audit or a repeat order does not have to rebuild it.
An equivalence claim is only as strong as the three numbers behind it: composition, tensile range at diameter, and test method. Send the drawing designation and the diameter, and the matching wire specification can be confirmed against all three standards before the order is placed.
