ASTM A751 Standard Test Methods and Practices for Chemical Analysis of Steel Products

Get Certified ASTM A751 Testing for Steel Products

ASTM A751 testing assists steel producers, suppliers, buyers, engineers, quality control personnel, and others in confirming the chemistry of steel products to the specification being tested for the product in question. Representative samples of steel are prepared by technicians, and a chemical analysis is conducted on them using the appropriate wet chemical or instrumental methods. The concentrations of the elements measured are compared to the chemical composition requirements of the specific steel product of interest. ASTM A751 testing can be used to verify material, accept or reject products, quality control, qualify suppliers, monitor production, and record chemical-composition results.

• Material Type: Steel, stainless steel, and related alloys.
• Analytical Techniques: Wet-chemical and instrumental methods.
• Chemical Requirements: Procedures for evaluating elemental composition against applicable product requirements.
• Product Analysis: Analysis of finished or semi-finished steel products as required by the applicable specification.
• Residual Elements: Guidance related to elements present in steel that may be subject to specified limits.
• Reference Standards: Use and treatment of appropriate reference materials or standards for chemical analysis.
• Data Treatment: Guidance for evaluating and reporting chemical-analysis data.
• Product Specifications: Application only when A751 or applicable portions are required by the relevant product specification.
• Conflict of Requirements: The applicable product specification takes precedence when its requirements conflict with A751.

What are the uses of ASTM A751 testing?

ASTM A751 testing is used to establish reliable chemical-composition data for steel products when chemical requirements are specified by an applicable product standard. The analytical results help determine whether a material conforms to its specified grade or composition. Common uses include:

• Chemical Composition Verification: Determines applicable elemental concentrations.
• Product Acceptance: Provides analytical data for evaluating steel against purchase or product requirements.
• Quality Control: Monitors consistency of steel production and processing.
• Grade Verification: Supports confirmation of the chemical composition associated with a specified steel grade.
• Residual Element Evaluation: Determines specified residual elements when required.
• Supplier Qualification: Provides chemical-analysis information for incoming steel products.
• Production Monitoring: Helps identify changes in steel chemistry during manufacturing.
• Reference Analysis: Provides applicable reference methods for resolving or evaluating chemical-composition results.
• Material Certification: Supports preparation of chemical-analysis records and certification documents.
• Specification Compliance: Provides data for comparison with the limits in the applicable product specification.

Which Materials Can Be Tested According to ASTM A751?

Chemical analysis of steel, stainless steel, and related alloys is covered by ASTM A751 when the applicable product specification includes the specified standard or parts of the standard. A751 is a standard for general chemical analysis and does not specify the elements being analyzed or the acceptance criteria, so the elements assessed and the acceptance criteria vary depending on the product specification. Materials can include:

• Carbon steel products
• Alloy steel products
• Stainless steel products
• Low-alloy steels
• High-alloy steels
• Steel bars and rods
• Steel plates and sheets
• Steel pipe and tubing
• Steel forgings
• Steel castings
• Steel wire and related products
• Other steel and related alloy products covered by applicable ASTM product specifications

Why is ASTM A751 Testing Important?

The composition of steel has a direct influence on the grade, processing behavior, mechanical properties, corrosion resistance, weldability, etc. When the procedures of ASTM A751 are specified in a product specification, a consistent framework for obtaining and reporting chemical-analysis data is provided. Chemical analysis provides reliable information to help distinguish material variations, to confirm specified composition, and to offer documented results for manufacturers and purchasers. Because A751 is used in conjunction with individual product specifications, the analytical result must always be interpreted against the requirements applicable to the particular steel product rather than against a universal A751 composition limit.

ASTM A751 Testing Process and Data Collection

Technicians first identify the steel product, grade, heat or lot information, and applicable product specification. Technicians select and prepare a representative sample according to the requirements of the applicable analytical method. During sample preparation, the analyst addresses surface contamination, scale, coatings, or other conditions that could affect the analysis. The analyst selects the appropriate wet-chemical or instrumental technique for the required elements. Sample preparation addresses surface contamination, scale, coatings, or other factors that may impact the analysis. The analyst chooses the right wet-chemical or instrumental method for the elements required. Instrumental systems are calibrated or verified with suitable reference material, and for wet-chemical procedures, suitable controlled reagents, measurements, and analytical steps are used. The technician records sample identification, preparation information, analytical equipment, reference materials, and relevant test conditions. 

Common Challenges and Troubleshooting

Poor sampling can result in poor test results for the steel product or for the test heat. Techs are encouraged to verify the sample identity before submitting it for analysis and to select representative sample material. Surface contamination, oxidation, scale, coatings, or residue are some of the factors that hinder some analytical techniques. Contamination-related errors can be minimized with proper cleaning and surface preparation. Measured concentrations may also be impacted by instrument drift and calibration. A suitable reference material, calibration standard, and verification procedure should be employed as per the analytical technique as required by the analyst.

• Analysis can provide results for carbon, manganese, silicon, phosphorus, sulfur, chromium, nickel, molybdenum, copper, vanadium, niobium, titanium, aluminum, nitrogen, boron, and other elements as required by the products. The concentrations of elements are generally given in mass per cent (%). Detection limit, significant figures, rounding and reporting should be done according to the appropriate approach and specification. 
• The sample identification, the steel grade, the information on heat or lot, the condition of the sample, the specimen preparation, the analytical instrument or the information on the wet-chemical method, the information on the calibration or the reference standard, and the relevant analytical conditions are noted by the technician. 
• The analyst notes the concentrations of elements measured, calculated or controlled if necessary, quality control observations, results for reference materials, and compares the results with the chemical requirements of the applicable product specification. 
• The material identification, product specification, grade, heat or lot information, analytical method, measured elemental concentrations, units, reference or calibration information, applicable chemical limits, conformity evaluation, and test conditions are included in the report. 
• Chemical-analysis technicians and analysts can provide consistent, reliable, and comparable results that comply with ASTM A751 when sampling, preparing specimens, using validated chemical-analysis methods, using appropriate reference materials, verifying instruments, controlling potential contamination, and systematically reporting results.

Link to ASTM A751