ASTM A726 Standard Specification for Cold-Rolled Magnetic Lamination Quality Steel, Semi-processed Types

Get Certified ASTM A726 Testing for Magnetic Lamination Steel Evaluation

Laboratories use ASTM A726 to evaluate cold-rolled magnetic lamination steel against specified magnetic and physical requirements. Accurate results depend on proper sample preparation, proper annealing, magnetic testing, dimensional measurement, and hardness evaluation. ASTM A726 uses the Epstein test method at a 60 Hz frequency and maximum flux density of 15 kG (1.5 T).

This standard includes:

• Specific material: Cold-rolled magnetic lamination quality steel and semi-processed magnetic lamination steel.
• Objective: To identify the materials required for magnetic use and low core loss performance.
• Magnetic properties: Qualitative development of annealing-specific core loss and permeability characteristics.
• Magnetic test method: Epstein testing at 60 Hz and a maximum flux density of 15 kG (1.5 T).
• Material composition: Low-carbon steel, which may include manganese, phosphorus, silicon, and aluminum additions.
• Thickness: Specified thicknesses include 0.0185, 0.022, 0.025, 0.028, and 0.031 in. (0.47, 0.56, 0.64, 0.71, and 0.79 mm).
• Heat treatment: User-applied lamination annealing develops the specified magnetic properties.
• Mechanical properties: Hardness tests and mechanical testing as specified.
• Test limitation: The specification does not cover all non-guaranteed types of core-loss and does not address all safety concerns related to core-loss use.

What are the uses of ASTM A726 testing?

ASTM A726 testing aids laboratories in assessing cold-rolled magnetic lamination steel for electrical and magnetic use. ASTM A726 is used to identify core-loss types and measure magnetic properties following the desired heat treatment of the core. Engineers and material suppliers use this standard to compare grades of steel and ensure that the material complies with the relevant magnetic and physical properties. This standard-

• Evaluates specific core-loss performance.
• Assists in choosing magnetic materials for electrical equipment.
• Assists in comparison of semiprocessed magnetic lamination steels.
• Evaluates hardness and selected mechanical properties.
• Helps to evaluate dimensions and surface quality.
• Helps manufacturers control material quality for magnetic applications.

Which Materials Can Be Tested Under ASTM A726?

ASTM A726 is a standard method that specifies requirements for cold-rolled carbon sheet steel for magnetic uses. Higher-quality grades use silicon-iron or silicon-aluminum-iron compositions and are referred to as semiprocessed magnetic lamination steels. The specification includes several core-loss types and specified sheet thicknesses.

Why is ASTM A726 important?

ASTM A726 specifies uniform requirements for semiprocessed cold-rolled magnetic lamination steels for electrical equipment. The specification enables manufacturers to manage core-loss performance, material size, hardness, and surface quality. It provides a uniform measure of magnetic properties after the required quality development anneal.

ASTM A726 Testing Process and Data Collection

Technicians first determine the steel grade, core loss type, thickness, surface condition, and requirements. They prepare representative specimens before magnetic testing; they conduct the necessary magnetic testing and quality-development annealing. The Epstein test method is used to evaluate the specimens at the desired frequency and flux density. Analysts record magnetic results together with hardness, dimensional, surface, and mechanical data when required. Engineers compare the measured properties with the requirements specified for the applicable type of steel.

Common Challenges and Troubleshooting

Reproducible and accurate results require correct specimen preparation, controlled annealing, accurate magnetic measurements, and proper dimensional evaluation. Common challenges include orientation of the specimen, annealing conditions, thickness measurement inaccuracies, magnetic test setup, and setup for hardness measurement. Laboratories should use calibrated equipment, maintain consistent heat-treatment conditions, and confirm the applicable material and core-loss requirements before testing.

• Specific core loss and other needed magnetic properties are reported by laboratories for the measured frequency and flux density at which the measurement was taken.
• Technicians note the steel identification, core-loss type, thickness, specimen orientation, heat-treatment conditions, and magnetic test configuration.
• Analysts record hardness, size, surface qualities, and mechanical tests.
• Engineers use the measured magnetic and physical properties to check the quality of the lamination steel samples tested.

What magnetic test does ASTM A726 use?

ASTM A726 uses the Epstein test method for magnetic evaluation. Magnetic testing is performed at 60 Hz and a maximum flux density of 15 kG (1.5 T).

What steel thickness does ASTM A726 cover?

The specification covers thicknesses including 0.0185, 0.022, 0.025, 0.028, and 0.031 in. (0.47, 0.56, 0.64, 0.71, and 0.79 mm). 

Does ASTM A726 require heat treatment?

Yes. The magnetic properties specified by ASTM A726 are developed through heat treatment by the user. The quality development anneal is an important part of the magnetic evaluation. 

Link to ASTM A726