ASTM A345 Standard Specification for Flat-Rolled Electrical Steels for Magnetic Applications

Get Certified ASTM A345 for Reliable Electrical Steel Procurement 

Under ASTM A345, certification confirms that flat-rolled electrical steels possess the magnetic, electrical, and mechanical properties outlined in a purchase order. Manufacturers rely on ASTM A345 certified testing to validate the core loss and other properties of a steel lot before the steel is accepted for transformers, motors, or magnetic laminations. Certification is used to verify compliance with the purchase order and to help ensure consistent magnetic quality. 

The primary purpose of ASTM A345 is to help buyers define the electrical properties of steel for magnetic use. Manufacturers, buyers, and engineers use this specification in procurement, quality control, and selection of materials.

The scope of ASTM A345 includes 

• Material type: flat-rolled grain-oriented, nonoriented, and magnetic lamination electrical steels, fully processed, semiprocessed, and thin-gauge.  
• Purpose: To provide general guidance for the procurement and delivery requirements.
• Properties measured: Core loss, electrical resistivity, ductility, lamination factor, and tensile or yield strength. 
• Method: The class of steel, core loss type/grade, and the controlling magnetic property are specified on the purchase order.
• Result: The material meets the property requirements of the purchase order. Controlled conditions for magnetic quality, sampling, testing, and packaged storage. 
• Test limitations: This specification does not include specific requirements but rather lists physical properties and ordering information to be taken into consideration when ordering material. 
• Use conditions: Applicable when an individual ASTM electrical steel specification does not exist.
• Application: Transformers, motors, generators, reactors, inductors, and electromagnetic equipment. 

What are the Uses of ASTM A345 Testing?

ASTM A345 provides a standard for ordering electrical steel with controlled magnetic qualities when no specific standard exists. The manufacturers then apply the stated requirements to manufacture and test the material. This standard-

• Provides general procedures for procuring flat-rolled electrical steel.
• Covers grain-oriented, nonoriented, and magnetic lamination steels.
• Guides buyers to specify core loss limits and the controlling magnetic property.
• Addresses electrical resistivity problems for the core loss limit and end use.
• Covers mechanical properties like lamination factor and ductility.
• Facilitates sampling, evaluation, and packing contracts.
• Complies with the respective ASTM electrical steel specifications. 

What Materials Fall Under ASTM A345? 

ASTM A345 applies to flat-rolled electrical steels (excluding transformer and distribution coils) designed for magnetic applications such as grain-oriented, nonoriented, and magnetic lamination steels. Common materials include fully-processed electrical steels, semiprocessed electrical steels, and thin-gauge electrical steels. When no ASTM material specification exists for the steel that the buyer requires, they will typically refer to this specification. Specifications A677, A683, A726, A840, A876, and A1086 are individual ASTM electrical steel specifications that meet this specification. 

Why is ASTM A345 Important? 

ASTM A345 provides buyers with a standard checklist of specifications for electrical steel. Typical maximum core loss specifications are normally included in electrical steels to ensure the correct material is supplied based on the clear limiting values. The magnetic properties of electrical steels directly affect energy efficiency and performance in transformers, motors, and generators. The standard allows users to include magnetic quality, sampling, testing, and packaging requirements in the purchase order. This allows material to be supplied under controlled conditions and meet the intended application requirements. This standard supports standardization and innovation in electrical and electronic components. 

ASTM A345 Evaluation Process and Data Collection

The process starts with the buyer specifying the type of steel and recording the core loss grade on the purchase order. The buyer then specifies the resistivity and mechanical property requirements. Then the supplier supplies the material, and the technician chooses the referenced methods for each property. Next, the technician tests for core loss, permeability, and mechanical properties and notes the findings. Lastly, the analyst checks the conformance of the results with the purchase order. 

Common Challenges and Troubleshooting

Accurate ASTM A345 results require clear purchase-order specifications and adherence to the applicable test methods. Common issues include magnetic property variations due to different grain orientations, damage to coating, which impacts insulation resistance, and dimensional variation, which impacts magnetic flux distribution. Controlled rolling processes, proper application of coating, and frequent quality checks of dimensions and magnetic checks are all used to reduce these problems. The purchaser is responsible for specifying limiting values of core loss and other magnetic properties required for the ordered material. 

• Laboratories report core loss in comparison to the limiting values as specified in the purchase order.
• Technicians describe the steel class, grade, and thickness being evaluated.
• Analysts note permeability, resistivity, and mechanical properties and link them to the evaluated lot.
• Engineers consider end use and the dominant magnetic property when interpreting results.
• Buyers use the results to support material acceptance for magnetic applications. 

Link to ASTM A345