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

How It Works

1. Select or Search

   Choose a supported grade, UNS number, EN number, or family filter, then keep the source-boundary notes visible.

2. Review Composition

   Use the local composition chart as a screening row, then verify against the current specification and material test report.

3. Check Machinability

   Treat the rating as a relative planning prompt, not guaranteed cutting data or tool-life proof.

4. Review Heat Treatment

   Use the notes to identify questions for supplier, heat treater, weld engineer, or materials review.

5. Compare Grades

   Compare 2-3 supported rows side by side before formal engineering, purchasing, or substitution approval.

Built For

• Machinists screening unfamiliar grade callouts before checking exact tooling data
• Purchasing agents flagging material-certification questions for supplier review
• Manufacturing engineers documenting preliminary machinability and condition assumptions
• Tool and die teams comparing local tool-steel prompt rows before source review
• Welding engineers identifying weldability and preheat questions for WPS review
• Students learning the AISI/SAE numbering system with source warnings visible

Features & Capabilities

29 Local Grade Rows

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 local composition ranges for alloying elements such as C, Mn, Cr, Mo, Ni, V, W, and Si.

Machinability Prompt

Relative percentage against an AISI 1212-style baseline, labeled as approximate planning data rather than guaranteed cutting data.

Quick Compare Mode

View 2-3 supported rows side by side for composition, machinability prompt, hardness field, and applications.

Family Filter Pills

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

PDF Export

Export grade screening data with source warnings for preliminary review notes.

Assumptions

• Composition rows are local source-pointer ranges that require current SAE/ASTM/EN and material-test-report verification
• Machinability ratings are relative planning prompts against an AISI 1212-style baseline, not guaranteed cutting data
• Heat-treatment notes are approximate prompts for supplier or heat-treater review, not production recipes
• Weldability flags are general prompts and do not replace qualified WPS/PQR or applicable code review
• Stainless UNS/EN and PREN rows are screening aids computed from midpoint assumptions where applicable
• Hardness rows are local prompts that require actual condition, heat treatment, and test-method verification

Limitations

• Composition ranges are nominal local rows; actual chemistry varies by mill, heat lot, specification, 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 are general prompts, not specific procedures or acceptance criteria
• Does not cover every international equivalent, mill variant, specialty grade, product form, or condition
• Weldability notes are general prompts; critical welding requires qualified procedure and applicable-code review

References

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

Frequently Asked Questions