AISI/SAE Steel Grade Decoder - Composition, Machinability & Heat Treatment
Decode Any Common Steel Grade for Alloy Chemistry, Properties, and Applications
Free steel grade calculator covering 29 local grade rows across five families: Carbon, Free-Machining, Alloy, Stainless, and Tool Steel. See local composition ranges, machinability prompts, heat-treatment notes, weldability flags, and applications with source-boundary warnings visible.
Includes a composition bar chart, quick-compare mode (2-3 grades side by side), and stainless UNS/EN/PREN screening rows. Use it for preliminary review only; current standards, mill certifications, material condition, tooling data, and qualified engineering or metallurgical review still control purchase, fabrication, welding, heat treatment, and substitution decisions.
Compare machinability ratings across materials
Machinability Comparison →Convert between hardness scales
Hardness Converter →Read the steel grades explained guide
Steel Grades Guide →Calculate speeds and feeds by material
Speeds & Feeds Calculator →How It Works
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Select or Search
Choose a supported grade, UNS number, EN number, or family filter, then keep the source-boundary notes visible.
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Review Composition
Use the local composition chart as a screening row, then verify against the current specification and material test report.
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Check Machinability
Treat the rating as a relative planning prompt, not guaranteed cutting data or tool-life proof.
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Review Heat Treatment
Use the notes to identify questions for supplier, heat treater, weld engineer, or materials review.
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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
- 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
Learn More
How to Read AWS Welding Electrode Numbers
What the digits and letters on a welding rod or wire mean: tensile strength, welding position, the last two digits for coating and current, low-hydrogen status, and the difference between E7018, ER70S-6, and E71T-1.
What the Markings on a Bolt Head Mean
How to read bolt head markings: SAE radial lines and the count-plus-two rule, the metric property class numbering, stainless A2/A4 corrosion classes, and ASTM structural grades.
ASTM Pipe Specs Explained
What A106, A53, A312, A333, A335, and A790 actually mean: seamless vs welded, high-temperature vs low-temperature service, and why A106 and A53 are not interchangeable.
Understanding AISI/SAE Steel Grade Numbers for the Machine Shop
What AISI and SAE steel grade numbers mean, how the 4-digit system works, and how to pick the right grade for machining, welding, and heat treatment.
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