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Nuts · GB/T 39 / ISO 4034

A4 Stainless Steel Square Nut — GB/T 39 / ISO 4034 (Series 075)

When Square Nut — GB/T 39 / ISO 4034 (Series 075) are required in A4 Stainless Steel, the alternative grades and the trade-offs between them matter as much as the dimensions. This page covers both, plus mechanical and corrosion data.

Why Choose A4 Stainless Steel for Square Nut — GB/T 39 / ISO 4034 (Series 075)

Specified for marine, coastal and chemical applications. For square nut — gb/t 39 / iso 4034 (series 075), this matters when superior, including marine and chloride environments is the primary requirement.

Mechanical & Physical Properties

Grade designationA4-80 (316)
Magnetic responseLargely non-magnetic
Service temperatureapprox. -200 °C to +400 °C
Corrosion characteristicSuperior, including marine and chloride environments

Corrosion Behavior in Service

A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Square Nut — GB/T 39 / ISO 4034 (Series 075) in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.

Comparable Grades

For Square Nut — GB/T 39 / ISO 4034 (Series 075), the alternative stainless grade is A2 (304). A2 (304) suits general indoor and outdoor service; A4 (316) adds molybdenum for marine and chloride environments. Where higher strength matters more than corrosion, switch to plated alloy-steel class 8.8 or 10.9.

Sizes of Square Nut — GB/T 39 / ISO 4034 (Series 075) Available in A4 Stainless Steel

SizePitch (mm)Width across flats s (mm)Nut height m (mm)Reference standard
M30.55.51.8GB/T 39 / DIN 562
M40.77.02.2GB/T 39 / DIN 562
M50.88.02.7GB/T 39 / DIN 562
M61.010.03.6GB/T 39 / DIN 562
M81.2513.04.8GB/T 39 / DIN 562
M101.517.06.0GB/T 39 / DIN 562
M121.7519.07.0GB/T 39 / DIN 562
M162.024.09.0GB/T 39 / DIN 562
M202.530.012.0GB/T 39 / DIN 562
M243.036.014.0GB/T 39 / DIN 562

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

Request a Quote

Adjust the parameters in the drawing above and click "Request this configuration" to send the exact specification straight to this form.

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Specification
Business Information

Dimensions & Specifications (GB/T 39 / ISO 4034)

SizePitch (mm)Width across flats s (mm)Nut height m (mm)Reference standard
M30.55.51.8GB/T 39 / DIN 562
M40.77.02.2GB/T 39 / DIN 562
M50.88.02.7GB/T 39 / DIN 562
M61.010.03.6GB/T 39 / DIN 562
M81.2513.04.8GB/T 39 / DIN 562
M101.517.06.0GB/T 39 / DIN 562
M121.7519.07.0GB/T 39 / DIN 562
M162.024.09.0GB/T 39 / DIN 562
M202.530.012.0GB/T 39 / DIN 562
M243.036.014.0GB/T 39 / DIN 562

Frequently Asked Questions

Can A4 Stainless Steel Square Nut — GB/T 39 / ISO 4034 (Series 075) gall during installation?

Yes — stainless on stainless is prone to thread galling under load, especially at smaller sizes. Use an anti-galling lubricant or wax thread compound, and slow the tightening rate where possible.

Is A4 Stainless Steel food-grade?

A4 (316) is the standard food-contact stainless grade in most jurisdictions, particularly where chloride exposure (brines, dairy CIP) is present.

Can A4 Stainless Steel Square Nut — GB/T 39 / ISO 4034 (Series 075) be used with aluminum?

Yes, but stainless drives mild galvanic corrosion of aluminum in wet service — isolate with a coating, sleeve or paint, or accept the trade-off if the joint is dry and indoor.

What's the service temperature limit for A4 Stainless Steel?

The practical service range is approx. -200 °C to +400 °C.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.