DIN 975 vs GB/T 15389: Differences between stainless steel threaded rod standards and selection guidelines

Nanning City, Guangxi, China - August 19, 2026 - If you have ever sourced stainless steel threaded rod for a project and found yourself comparing product specifications from different suppliers, you have probably encountered both DIN 975 and GB/T 15389 standards. These two standards look similar on the surface - both define fully threaded rods made from stainless steel - but they are not identical, and choosing the wrong one can lead to fitment issues, mismatched strength grades, or even project delays. If you are new to these standards, you probably have two pressing questions. First, what exactly is the difference between DIN 975 stainless steel threaded rod and GB/T 15389, and can they be used interchangeably? Second, how do I know which standard to specify for my application - whether I am working on construction, equipment installation, or industrial maintenance? In this guide, we will break down the key differences between these two standards, compare their dimensional ranges, strength grades, and material specifications, and give you practical selection criteria. By the time you finish reading, you will know exactly which stainless steel threaded rod standard belongs in your project.

What are threaded rods and why do standards matter?

A threaded rod - also known as a fully threaded stud, all-thread rod, or stainless steel threaded rod - is a long, straight metal bar with continuous external threads along its entire length. Unlike bolts that have a head, threaded rods are headless fasteners designed to be used with nuts on both ends, making them ideal for applications where you need to connect two components or create a suspended support system.

Standards like DIN 975 and GB/T 15389 matter because they define the critical specifications that ensure compatibility, safety, and performance. When you specify a stainless steel threaded rod [https://www.aozhanfasteners.com/stainless-steel-thread-rod-product/] to a particular standard, you are guaranteeing that the rod will have the correct thread dimensions, strength properties, and material composition for your application. Using a rod that does not meet the required standard can lead to thread mismatch, insufficient load capacity, or premature corrosion failure.

Image: https://ecdn6.globalso.com/upload/p/631/image_other/2026-08/stainless-steel-threaded-rods-1.webp [https://www.aozhanfasteners.com/stainless-steel-thread-rod-product/]

DIN 975: The German standard for threaded rods

DIN 975 is the German industrial standard for metric threaded rods. Although the standard has been formally withdrawn and integrated into DIN 976-1, it remains the most widely recognized and referenced threaded rod standard globally. DIN 975 covers fully threaded rods made from carbon steel, stainless steel, and alloy steel.

Key specifications of DIN 975

Thread size range: M2 to M64, with coarse and fine thread options

Standard lengths: Typically 1 meter, 2 meters, and 3 meters, with custom lengths available

Stainless steel grades: A2 (304 stainless steel) and A4 (316 stainless steel)

Strength grades for stainless steel: Class 70 (tensile strength greater than or equal to 700 MPa) for diameters up to M24; Class 50 ( greater than or equal to 500 MPa) for diameters M27 and above

Thread tolerance: 6g per ISO 724 and ISO 965-1

Common applications: Construction, suspension systems, pipe supports, machinery, and MRO

One important feature of DIN 975 is the color-coding system used by many manufacturers: A2 (304) rods are often marked with blue or green ends, while A4 (316) rods are marked with red ends. This makes visual identification quick and reliable on the job site.

GB/T 15389: The Chinese national standard for threaded rods

GB/T 15389 is the Chinese national standard for threaded rods. The original version, GB/T 15389-1994, was issued in December 1994 and specified threaded rods in sizes M4 to M42. This standard non-equivalently adopted DIN 975:1986, meaning it was based on the German standard but with modifications for the Chinese market.

In October 2025, a major revision - GB/T 15389-2025 - was issued, taking effect on February 1, 2026. This new version significantly expands the standard's scope and updates its technical requirements.

Key specifications of GB/T 15389-2025

Thread size range: Coarse threads M2 to M68; fine threads M8 times 1 to M72 times 6

Standard lengths: Expanded length series with theoretical mass tables

Stainless steel grades and performance grades: A2-50, A2-70, A4-50, A4-70, A4-80, D4-70, D4-80, D6-70, D6-80

Carbon steel performance grades: 8.8, 10.9, 12.9 (added in 2025 revision)

New features in 2025 revision:

Added threaded rods with chamfered ends on both sides

Added passivation requirements for stainless steel rods

Added non-electrolytic zinc flake coating and hot-dip galvanizing requirements for steel rods

Added marking and labeling requirements

DIN 975 vs GB/T 15389: Head-to-head comparison

Feature

DIN 975 threaded rod

GB/T 15389-2025 threaded rod

Standard Origin

German industrial standard

Chinese national standard

Status

Withdrawn (integrated into DIN 976-1)

Current (effective Feb 1, 2026)

Thread Size Range

M2 - M64

M2 - M68 (coarse); M8 times 1 - M72 times 6 (fine)

Stainless Steel Grades

A2 (304), A4 (316)

A2, A4, D4, D6

Stainless Performance Grades

Class 70 ( less than or equal to M24), Class 50 ( greater than or equal to M27)

A2-50, A2-70, A4-50, A4-70, A4-80, D4-70, D4-80, D6-70, D6-80

Carbon Steel Grades

Class 4.6, 4.8, 8.8, 10.9, 12.9

8.8, 10.9, 12.9

Thread Tolerance

6g

Metric coarse thread, 6g tolerance

Surface Treatment Requirements

Varies by manufacturer

Passivation for stainless; zinc flake or hot-dip galvanizing for steel

Typical Applications

Construction, suspension, pipe supports, machinery, MRO

Construction, equipment installation, power plant construction

Can DIN 975 and GB/T 15389 be used interchangeably?

This is one of the most common questions we hear from procurement professionals and engineers. The short answer is: in many cases, yes - but with important caveats.

GB/T 15389-1994 was non-equivalently adopted from DIN 975:1986, meaning the two standards share a common origin. For basic applications with standard tolerance requirements, DIN 975 and GB/T 15389 threaded rods in corresponding sizes and grades offer broad interchangeability. Many manufacturers produce threaded rods that comply with both standards simultaneously.

However, for critical or high-reliability applications, we recommend specifying the standard that matches your project's design requirements. Here is why:

Thread size coverage: DIN 975 covers M2 to M64, while GB/T 15389-2025 extends to M68 for coarse threads and M72 times 6 for fine threads. For sizes above M64, GB/T 15389 offers options that DIN 975 does not.

Performance grade differences: DIN 975 stainless steel rods typically use Class 70 ( greater than or equal to 700 MPa) for diameters up to M24 and Class 50 ( greater than or equal to 500 MPa) for larger diameters. GB/T 15389-2025 offers a wider range of stainless performance grades, including the higher-strength A4-80 ( greater than or equal to 800 MPa). If your application requires A4-80 grade, GB/T 15389 is the standard to specify.

Surface treatment requirements: GB/T 15389-2025 now includes specific passivation requirements for stainless steel threaded rods, which helps ensure consistent corrosion resistance. DIN 975 does not specify passivation requirements, leaving this to manufacturer discretion.

Standard status: DIN 975 has been formally withdrawn and integrated into DIN 976-1. While products are still manufactured to DIN 975 specifications, some jurisdictions and quality systems may require compliance with the current standard.

Stainless steel grades: A2 vs A4 (304 vs 316)

When selecting a stainless steel threaded rod [https://www.aozhanfasteners.com/stainless-steel-thread-rod-product/], the choice between A2 (304) and A4 (316) is critical for long-term performance.

A2 stainless steel (304) contains 18% chromium and 8% nickel. It offers excellent general corrosion resistance for indoor and moderate outdoor applications. A2 is the standard choice for most construction, machinery, and general industrial uses.

A4 stainless steel (316) adds 2-3% molybdenum to the alloy, providing superior resistance to pitting and crevice corrosion caused by chlorides in saltwater and chemical environments. A4 is the standard recommendation for marine applications, coastal infrastructure, and chemical processing. The red end marking used by many manufacturers makes A4 rods easy to identify on site.

For applications exposed to saltwater, deicing salts, or aggressive chemicals, choose A4 (316) stainless steel threaded rod. For general indoor or moderate outdoor use, A2 (304) offers excellent value.

Practical selection guidelines

When choosing between DIN 975 and GB/T 15389 stainless steel threaded rods, use these guidelines:

Choose DIN 975 when:

Your project follows German or international standards (DIN, ISO)

You need sizes within the M2-M64 range

Standard Class 70 or Class 50 stainless grades are sufficient for your application

Your procurement team is familiar with DIN specifications

You are sourcing from European or internationally oriented suppliers

Choose GB/T 15389 when:

Your project follows Chinese national standards

You need sizes above M64 or fine thread options up to M72 times 6

You require higher-strength stainless grades like A4-80 ( greater than or equal to 800 MPa)

You need documented passivation treatment for stainless steel rods

You are sourcing from Chinese manufacturers who produce to GB standards

For most practical purposes, DIN 975 and GB/T 15389 threaded rods in corresponding sizes and grades can be used interchangeably. Many reputable stainless steel threaded rod manufacturers produce products that meet both standards simultaneously. When in doubt, consult your supplier and request documentation confirming compliance with your required standard.

Contact Us

Not sure whether DIN 975 stainless steel threaded rod or GB/T 15389 is right for your project? Our team works with leading stainless steel threaded rod manufacturers and DIN 975 threaded rod manufacturers to source high-quality fasteners for construction, industrial, and marine applications. Whether you need threaded rod prices for a large order or assistance with technical specifications, we are here to help. Reach out today for a consultation or a quote tailored to your needs.

FAQ

Q1: What is the main difference between DIN 975 and GB/T 15389 threaded rods?

DIN 975 is the German industrial standard for metric threaded rods, covering sizes M2 to M64 with stainless grades A2 and A4. GB/T 15389 is the Chinese national standard, with the 2025 revision covering coarse threads M2 to M68 and fine threads M8 times 1 to M72 times 6. GB/T 15389-2025 also offers a wider range of stainless performance grades, including A4-80 ( greater than or equal to 800 MPa), and includes specific passivation requirements for stainless steel rods. The two standards share a common origin - GB/T 15389-1994 non-equivalently adopted DIN 975:1986 - and are broadly interchangeable in corresponding sizes and grades.

Q2: Can I use a DIN 975 threaded rod in a project that specifies GB/T 15389?

In most cases, yes - provided the size and grade match your requirements. Many manufacturers produce threaded rods that comply with both standards simultaneously. However, for critical applications or when your project requires specific GB/T 15389 features - such as A4-80 grade, passivation treatment, or sizes above M64 - you should specify GB/T 15389. Always confirm with your supplier that the product meets your required standard and request documentation.

Q3: What is the difference between A2 and A4 stainless steel threaded rods?

A2 (304) stainless steel offers excellent general corrosion resistance for indoor and moderate outdoor applications. A4 (316) stainless steel contains molybdenum, providing superior resistance to pitting and crevice corrosion caused by chlorides in saltwater and chemical environments. For marine applications, coastal infrastructure, or exposure to deicing salts, choose A4. For general construction and indoor use, A2 offers excellent value. A4 rods are often marked with red ends for easy identification.

About us

Established in 2012, Aozhan Hardware Fastener Co., Ltd. is a company specializing in the production and sale of quality hardware fasteners. We are committed to providing our customers with high quality and reliable products to solve the pain points in the industry.

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