Composition Analyzer

Analyze an alloy's chemical composition. See element breakdown, identify the alloy family, and compare to specifications.

Analysis

How to Use

  1. 1
    Enter the Alloy Composition

    Input the weight percentages of each element in the alloy, or select a standard grade and modify individual elements to represent measured or alternative compositions.

  2. 2
    Check Against Standard Specification Limits

    Select the target specification (e.g., ASTM A276, AMS 2631, or EN 10088) to compare the entered composition against the specification's minimum and maximum limits for each element.

  3. 3
    Review the Conformance Report and Property Estimates

    The tool highlights any out-of-specification elements and provides estimated carbon equivalent, PREN (for stainless steels), and predicted mechanical property ranges based on the composition.

About

Chemical composition is the primary determinant of an alloy's properties — its mechanical performance, heat treatability, weldability, corrosion resistance, and machinability all trace back to the concentrations and interactions of its constituent elements. While datasheets provide properties for nominal compositions, real heats of material vary within specification limits, and these variations can meaningfully affect performance in demanding applications.

The AlloyFYI Composition Analyzer provides a compositional compliance check against major material standards, immediately identifying heats that fall outside specification limits before they are used in production. The integrated property estimation functions — carbon equivalent, PREN, predicted strength ranges based on regression models — allow engineers to assess whether a borderline-compliant heat will meet the structural performance requirements of the application. This capability is particularly valuable in incoming material inspection, material substitution evaluation, and failure investigation, where understanding the relationship between a specific composition and expected properties is essential.

FAQ

What are the effects of sulfur and phosphorus in steel?
Sulfur and phosphorus are generally harmful impurities in steels, controlled to low levels in most specifications. Sulfur forms manganese sulfide (MnS) inclusions that reduce ductility and toughness in the through-thickness direction (causing lamellar tearing in welded structures) and lower corrosion resistance. Re-sulfurized free-machining grades (AISI 1213, 12L14) intentionally retain higher sulfur (0.26–0.35%) to improve chip-breaking and surface finish in automatic screw machine operations. Phosphorus forms iron phosphide, which segregates to grain boundaries and dramatically reduces Charpy impact toughness, particularly at low temperatures. Clean steel practices (ladle metallurgy, vacuum degassing) reduce both elements to below 0.015% in premium grades.
What role does silicon play in alloy steels?
Silicon is added to steel primarily as a deoxidizing agent during steelmaking (killed steels), typically at 0.15–0.35%, to remove dissolved oxygen and prevent porosity in ingots. At higher levels (1–2%), silicon increases the elastic limit and fatigue strength of spring steels (AISI 9260). In electrical steels used for transformer laminations, silicon at 1.5–4.5% dramatically reduces electrical conductivity (increasing resistivity) and thus reduces eddy current losses. In austenitic stainless steels, silicon improves oxidation resistance at elevated temperatures. Above approximately 0.5%, silicon increases hardenability and raises the ferrite-to-austenite transition temperature.
How does nitrogen affect stainless steel properties?
Nitrogen is a powerful austenite stabilizer and solid solution strengthener in austenitic and duplex stainless steels. It raises yield strength by approximately 40 MPa per 0.1% N addition and dramatically improves pitting corrosion resistance (the PREN formula includes a 16×%N term). Modern nitrogen-alloyed duplex grades (2205: ≈0.17% N; 2507: ≈0.28% N) achieve their superior combination of strength and corrosion resistance primarily through controlled nitrogen additions. Precipitation of chromium nitrides must be avoided during heat treatment, as they reduce both toughness and corrosion resistance in a manner analogous to carbide sensitization.
What is the effect of copper on steel corrosion resistance?
Copper at 0.25–0.55% in low-alloy weathering steels (Cor-Ten, ASTM A588) promotes the formation of a tightly adherent, protective rust layer (patina) of copper-alloyed iron oxyhydroxides when cyclically wetted and dried in outdoor exposure. This patina layer forms within 18–24 months of outdoor exposure and then stabilizes, providing long-term corrosion protection without paint or galvanizing. The patina does not form in constantly wet or submerged conditions, which limits weathering steel use to well-drained outdoor structures. Copper also contributes to age hardening in some precipitation-hardening stainless steels and increases resistivity in electrical steels.
How is alloy composition verified for positive material identification (PMI)?
Positive material identification (PMI) is the field verification of alloy composition for safety-critical applications (pressure vessels, pipelines, aerospace). X-ray fluorescence (XRF) analyzers provide rapid semi-quantitative analysis of elements from sodium to uranium without sample preparation, with accuracy sufficient to distinguish major alloy grades (e.g., carbon steel vs. stainless steel vs. nickel alloy). Optical emission spectrometry (OES) with portable or laboratory instruments provides higher accuracy and can detect light elements (C, N, O) that XRF misses. Both methods are compared against the nominal specification composition to verify correct material use and detect material mix-ups.
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