AISI/SAE Steel Grade Decoder — Composition, Machinability & Heat Treatment

How It Works

1. Select or Search

   Choose a grade or type a number to search. Organized by family: Carbon, Free-Machining, Alloy, Stainless, and Tool Steel.

2. Review Composition

   See full alloy chemistry with composition bar chart for visual comparison.

3. Check Machinability

   Rating shown as percentage relative to AISI 1212 baseline (100%).

4. Review Heat Treatment

   Notes on heat treatment response and weldability for process planning.

5. Compare Grades

   Select 2-3 grades for side-by-side comparison table.

Built For

• Machinists looking up unfamiliar grade callouts before setting speeds and feeds
• Purchasing agents verifying material certs match specified grades
• Manufacturing engineers selecting grades based on machinability and properties
• Tool and die makers choosing tool steel grades for specific applications
• Welding engineers evaluating weldability and preheat requirements
• Students learning the AISI/SAE numbering system

Features & Capabilities

29 Steel Grades

Carbon (1018, 1045, 1095), Free-Machining (1215, 12L14), Alloy (4130, 4140, 4340, 8620), Stainless (303, 304, 316, 17-4PH), Tool (A2, D2, O1, S7, H13, M2), and more.

Composition Bar Chart

Visual chart showing percentage of each alloying element (C, Mn, Cr, Mo, Ni, V, W, Si).

Machinability Rating

Percentage relative to AISI 1212 = 100%. Free-machining steels: 125-170%. Stainless/tool steels: 30-60%.

Quick Compare Mode

View 2-3 grades side by side comparing composition, machinability, hardness, and applications.

Family Filter Pills

Color-coded filters for Carbon, Free-Machining, Alloy, Stainless, and Tool Steel families.

PDF Export

Export grade data as branded PDF for material requisitions or training documentation.

Assumptions

• Chemical composition ranges per SAE J403 (carbon steels), SAE J404 (alloy steels), and ASTM A240 (stainless steels)
• Machinability ratings relative to AISI 1212 free-machining steel as the 100% baseline per AISI standard methodology
• Heat treatment response based on typical commercial practice for each grade (oil quench, water quench, air cool)
• Weldability assessment based on carbon equivalent formula CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15
• Tool steel classifications per AISI designation system (A, D, H, M, O, S, T, W series)
• Hardness ranges listed for both annealed and heat-treated conditions where applicable

Limitations

• Composition ranges are nominal; actual chemistry varies by mill, heat lot, and country of origin
• Machinability ratings are single-point estimates that do not capture variation across different machining operations
• Does not include all AISI/SAE grades; covers 29 commonly encountered grades for shop reference
• Heat treatment parameters (austenitizing temp, quench media, temper temp) are general guidance, not specific procedures
• Does not cover international equivalents (DIN, JIS, GB, BS EN) for cross-referencing foreign material specifications
• Weldability notes are general guidance; critical welding requires a qualified WPS per AWS D1.1 or ASME Section IX

References

• SAE J403 - Chemical Compositions of SAE Carbon Steels
• SAE J404 - Chemical Compositions of SAE Alloy Steels
• ASTM A240 - Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip
• ASM Metals Handbook, Volume 1 - Properties and Selection: Irons, Steels, and High-Performance Alloys
• AISI Steel Products Manual - Machinability Rating Methodology and Data Tables
• Machinery's Handbook, 31st Edition - Steel Classification, Properties, and Heat Treatment
• ASTM A681 - Standard Specification for Tool Steels Alloy

Frequently Asked Questions