SAE J1072: The Essential Guide to Sintered Tool Materials Classification

This article explains how to use SAE J1072, a recommended practice for identifying and classifying sintered tool materials such as ceramics, cemented carbides, and cermets. The standard uses a systematic letter-number “line call out” system to clearly define material composition and key properties. By adopting this common language, engineers and suppliers can ensure consistent material selection and manufacturing quality.

Understanding the Basic Classification (5‑Digit Code)

The first part of the system is a five-digit code that identifies the material compound, binder, and base metals. The digits follow a set order defined in Table 1.

Digit Position	Meaning	Code Options
1st	Material Compound	1 = Nitride, 2 = Carbide, 3 = Oxide, 9 = Other
2nd	Binder Metal	0 = None, 1 = Nickel, 2 = Iron, 3 = Cobalt, 9 = Other
3rd	Predominating Base Metal	0 = None, 1 = Columbium, 2 = Tungsten, 3 = Titanium, 4 = Tantalum, 5 = Chromium, 6 = Aluminum, 9 = Other
4th & 5th	Other Base Metals	Same as 3rd digit options; use 0 if not present

Examples from the standard:

SAE J1072 23200 – Tungsten carbide (2) with cobalt binder (3) and no other base metals.
SAE J1072 30600 – Aluminum oxide ceramic (3, oxide), no binder, no base metal.
SAE J1072 23234 – Tungsten, titanium, and tantalum carbide with cobalt binder.

Specifying Properties with Suffix Requirements

After the basic classification, suffix letters followed by numbers define the required properties. The table below summarizes the available suffixes.

Suffix	Property	Format Example	Key Tolerance
A	Binder Metal Quantity (%)	A045 (4.5% binder)	±5% of specified quantity
B	Base Metal Quantity (%)	B096B047 (9.6% and 4.7%)	±5% each
C	Hardness (Rockwell A)	C922 (92.2 RA)	±0.3 RA if <89.9, ±0.2 if ≥90.0
D	Specific Gravity (g/cm³)	D126 (12.6 g/cm³)	±0.1 g/cm³
E	Grain Size per SAE J439	E231 (rating 231)	N/A
F	Apparent Porosity per SAE J439	F421 (A-4, B-2, C-1)	Maximum levels
G	Transverse Rupture Strength (psi × 1000)	G095 (95,000 psi)	Minimum
Z	Other Properties (spelled out)	Z1 = thermal expansion; Z2 = coating	As defined

Note: Only include the suffixes that are needed for the application. Avoid combining specifications that are not commercially feasible.

🛠️ Engineering Design Insight

Using SAE J1072 ensures that all parties – from design to procurement to production – speak the same language. The precise tolerances (e.g., hardness ±0.2 RA for hard grades) reduce variability and improve process capability. The suffix system also allows engineers to prioritize the most critical properties without over-specifying.

Frequently Asked Questions

How do I code a simple tungsten‑cobalt grade?

Use the basic classification 23200 (carbide, cobalt binder, tungsten base metal). Add suffix A for binder percentage if needed, e.g., A100 for 10.0% cobalt.

What does suffix C mean and how are tolerances applied?

Suffix C specifies Rockwell A hardness. For example, C890 means 89.0 RA. The actual product range is ±0.3 when the target is below 89.9, and ±0.2 when it is 90.0 or above. So C922 (92.2 RA) allows 92.0–92.4.

How do I specify a material with properties not covered by standard suffixes?

Use suffix Z followed by a number, and write out the requirement. For instance, Z1 could describe a specific thermal expansion value or a coating type. Do not use Z if there is already a dedicated suffix letter.

⚠️ Common Mistakes to Avoid

Using the wrong compound digit (e.g., 1 for nitride when specifying a carbide).
Omitting required base metal suffixes when multiple base metals are present.
Specifying suffix Z for properties that have standard letters (A–G).
Assigning tolerances that are not realistic for the chosen composition.

For full details, always refer to the latest versions of SAE J1072, SAE J439, and ASTM B406.