Introduction to the JIS Designation System

Understanding the Japanese Industrial Standards System

The Japanese Industrial Standards (JIS) are developed by the Japanese Industrial Standards Committee (JISC) in Tokyo with the primary aim of promoting standardization across Japan's industrial sectors. The specification system follows a logical structure that begins with the prefix "JIS," followed by a letter representing a specific industrial division, and concludes with four digits that identify the particular standard.

JIS Classification Divisions

The JIS system organizes standards into various divisions, each represented by a specific letter. The major divisions include:

• A – Civil Engineering and Architecture
• B – Mechanical Engineering
• C – Electronic and Electrical Engineering
• D – Automotive Engineering
• E – Railway Engineering
• F – Shipbuilding
• G – Ferrous Materials and Metallurgy
• H – Nonferrous Materials and Metallurgy
• K – Chemical Engineering

Click on the below links to see standard lists for the following categories:

• Iron, Structural and Constructional Steels, Stainless Steels, Coated Steels
• Castings, Forgings, Welding and Filler Materials, Powder Metallurgy/Sintered Materials

Global Influence and Adoption

Japanese JIS standards have established themselves as influential references throughout Asia and the Pacific regions. Many countries, including Korea, China, and Taiwan, have developed their national standards systems using JIS specifications as foundational models, particularly in steel manufacturing and metallurgy.

Steel Designation Examples

To better understand how the JIS system works in practice, consider these examples:

Example 1: JIS G3445 STKM11A represents a low-carbon tube steel containing 0.12% C, 0.35% Si, 0.60% Mn, 0.04% P, and 0.04% S.

Example 2: JIS G4403 SKH2 (equivalent to AISI T1 Grade) designates a tungsten high-speed tool steel containing 0.73-0.83% C, 3.8-4.5% Cr, 0.4% Mn, 0.4% Si, 0.8-1.2% V, and 17-19% W.

Stainless Steel Designation System

For stainless steels, Japan has largely incorporated the American Iron and Steel Institute (AISI) numbering system into its own framework. For instance, SUS 304 in the Japanese system corresponds to Type 304 stainless steel in the AISI system. The JIS system uses additional prefixes for specialized materials:

• SUH numbers designate heat-resistant alloys (e.g., SUH 310)
• SCS and SCH numbers identify stainless steel castings

In the SUS designation, each letter has specific meaning: the first "S" stands for Steel, "U" represents "Use" (indicating special applications), and the second "S" denotes "Stainless."