ASTM A500 Standard Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes

Get Certified ASTM A500 Testing for Cold-Formed Welded and Seamless Carbon Steel 

ASTM A500 testing allows sales agents, manufacturers, engineers, fabricators, contractors, and quality controllers of structural tubing to confirm that the carbon-steel tubing meets specification requirements. Technicians perform chemical analysis, tensile testing, flattening or other suitable tests, dimensional testing, and visual examination of representative samples of tubing. Qualified testing is a method that gives recorded facts and information regarding the material of the tubing, its strength, ductility, size, and workmanship. The results can assist in quality control of production, supplier qualification, material acceptance, fabrication, and verification of structural materials.

• Material Type: Carbon steel structural tubing.
• Manufacturing: Cold-formed welded and seamless production.
• Cross-Section: Round, square, rectangular, and special structural shapes.
• Product Form: Welded and seamless tubing.
• Applications: Welded, riveted, or bolted construction of bridges and buildings and general structural purposes.
• Chemical Requirements: Limits for carbon, manganese, phosphorus, sulfur, and copper.
• Mechanical Requirements: Tensile and flattening test requirements and applicable mechanical properties.
• Dimensional Requirements: Outside dimensions, wall thickness, length, twist, and applicable permissible variations.
• Heat Treatment: Grade D requires heat treatment.
• Manufacturing Limits: Periphery up to 88 in. (2235 mm) and specified wall thickness up to 1.000 in. (25.4 mm).
• Finish: Tubing must have a workmanlike finish and be free from defects that interfere with its intended use.
• Limitations: The specification notes that products may not be suitable for applications where low-temperature notch toughness is important.

What are the uses of ASTM A500 Testing?

ASTM A500 testing verifies the quality and specification conformity of structural tubing before fabrication or installation. Manufacturers use the requirements to control production, while purchasers and engineers use test results to evaluate supplied tubing. The uses cover:

• Structural Tubing Quality Control: Verifies production against specification requirements.
• Material Acceptance: Provides documented evidence for evaluating supplied tubing.
• Tensile Property Verification: Determines applicable yield strength, tensile strength, and elongation.
• Flattening Evaluation: Examines tubing behavior under the specified flattening test.
• Dimensional Inspection: Checks outside dimensions, wall thickness, length, twist, and applicable tolerances.
• Chemical Composition Verification: Confirms applicable elemental limits.
• Supplier Qualification: Supports evaluation of tubing from different manufacturers or production sources.
• Fabrication Control: Helps ensure tubing is suitable for subsequent welding, bolting, or structural fabrication.
• Structural Material Verification: Provides test data for engineering and construction documentation.

Which Materials Can Be Tested According to ASTM A500?

ASTM A500 covers welded and seamless cold-formed carbon-steel structural tubing. They are suitable for structural construction and general structural use and can be round, square, rectangular, or special structural cross-sections. Materials and products covered include:

• Welded carbon-steel structural tubing
• Seamless carbon-steel structural tubing
• Round structural tubing
• Square structural tubing
• Rectangular structural tubing
• Special-shape structural tubing
• Cold-formed structural tube sections
• Tubing for bridge construction
• Tubing for building construction
• Tubing for welded, riveted, or bolted structural assemblies

Why is ASTM A500 Testing Important?

ASTM A500 testing matters because structural tubing must have known mechanical and dimensional properties for manufacturing and use. Chemical analysis is used to confirm the specified steel composition, and tensile and other mechanical tests can indicate the strength and ductility of the steel. Dimensional and visual inspections are also significant due to the possibility of differences in wall thickness, exterior dimensions, twist, length, or surface condition, which may impact fabrication and structural assembly. In addition, ASTM A500 states that its product may not be appropriate for dynamically loaded welded parts requiring low-temperature notch toughness.

ASTM A500 Testing Process and Data Collection

Technicians first identify representative structural-tubing samples according to the applicable grade, heat, product form, cross-sectional shape, dimensions, and manufacturing method. The tubing is inspected for surface condition and measured for outside dimensions, wall thickness, length, twist, and other applicable characteristics. The technician prepares representative specimens for tensile and flattening evaluations. During tensile testing, the technician records specimen dimensions, applied force, deformation, yield behavior, tensile load, and elongation. Chemical specimens are analyzed to determine the applicable elemental composition, while flattening evaluations are performed using the required specimen configuration and loading conditions. The technician records specimen identification, tubing dimensions, test equipment, test conditions, and measured observations. The analyst reviews the chemical and mechanical results and compares them with the requirements applicable to the specified ASTM A500 product.

Common Challenges and Troubleshooting

Inaccurate dimensional measurements, improper specimen preparation, equipment calibration problems, incorrect sample identification, or inconsistent mechanical-test alignment can all have an effect on ASTM A500 testing. Care should also be taken with the welded longitudinal area when preparing specimens and evaluating them when using welded tubing. Contamination and improper sample preparation can cause differences in chemical analysis results. The geometry of the specimens, the way they are gripped, aligned, and deformed, and the method used to measure the deformation can all influence tensile results. 

• Report chemical analysis results for the applicable elements, and report mechanical results (yield strength, tensile strength, and elongation) according to the specified grade. Tensile strength and yield strength are generally reported in MPa when SI units are used, while elongation is reported as a percentage (%).
• The technician records specimen identification, tubing shape, outside dimensions, wall thickness in mm, specimen dimensions, length, grade, heat information, test conditions, and equipment information. The analyst documents chemical composition, yield strength, tensile strength, elongation, flattening observations, dimensional measurements, surface-condition observations, and other required evaluation data.
• The report includes tubing identification, manufacturer or heat information (as applicable), grade, manufacturing type, cross-sectional shape, dimensions, chemical analysis results, tensile properties, elongation, flattening test observations, dimensional results, workmanship observations, and applicable test conditions. 
• With the same sample preparation, calibrated test equipment, controlled tensile and flattening tests, dimensional measurements, appropriate chemical analysis, and recorded data, the same sample prepared by technicians or technoanalysts will yield the same ASTM A500 results.

Link to ASTM A500