ASTM A664 Identification of Standard Flat-rolled Electrical Steel Grades

Get Certified ASTM A664 for Uncompromising Quality and Project Success

Manufacturers use this method to confirm that flat-rolled electrical steel meets the core-loss requirements of a chosen specification. Accurate grade designation supports consistent magnetic performance across production batches and reduces the risk of material mismatch in critical applications. Matestlab supports manufacturers with calibrated core-loss testing and experienced analysts who verify grade designations against Specifications A677, A683, A726, A876, and A1086.

The scope of the ASTM A664 standard includes

• Material type: Flat-rolled electrical steel, including nonoriented and grain-oriented grades.
• Purpose: Standardization of the core-loss-type designation system for electrical steel grades.
• Properties evaluated: Specific core loss at a stated peak induction and frequency.
• Testing Method: Core loss measurement using the Epstein test method or single sheet tester, referenced through Test Methods A343 and A341.
• Result: A core-loss-type designation code applied for ordering and identification purposes.
• Test Limitations: Grade identification applies only to material that meets every requirement of the governing individual specification.
• Use conditions: Core loss measurement occurs at a stated peak induction and frequency, commonly 1.5 T (15 kG) and 60 Hz.
• Applications: Compatible with Specifications A677, A683, A726, A876, and A1086 for nonoriented and grain-oriented electrical steel.

What are the uses of ASTM A664 Testing?

ASTM A664 covers electrical steel ordering, quality verification, and cross-specification consistency. Manufacturers rely on the designation system to communicate core-loss performance clearly to purchasers. Testing laboratories apply the same codes across Specifications for consistent grading. This standard-

• Standardizes core-loss-type designations across related electrical steel specifications.
• Simplifies ordering and identification for manufacturers, purchasers, and mills.
• Supports quality verification of nonoriented and grain-oriented electrical steel grades.
• Reduces the risk of material mismatch in transformers, motors, and generators.
• Enables global trade through a widely recognized designation system.

Which Materials Can Be Tested Under ASTM A664?

ASTM A664 applies to flat-rolled electrical steel, including nonoriented and grain-oriented grades produced under Specifications A677, A683, A726, A876, and A1086. Magnetically soft iron and steel, along with low-carbon steels and iron alloys containing silicon or aluminum, qualify for grade identification under this practice. Analysts match the specimen’s governing specification to the correct core-loss-type designation before testing. A specimen that falls outside every requirement of its governing specification does not qualify for a standard grade designation.

Why is ASTM A664 Important?

The significance of ASTM A664 lies in the direct link between a consistent designation system and reliable electrical steel procurement. Mill-specific naming creates confusion when manufacturers and purchasers compare core-loss performance across different sources. Consistent application of this practice lets manufacturers and purchasers order, identify, and verify electrical steel grades with confidence.

ASTM A664 Testing Process and Data Collection 

ASTM A664 examination begins with specimen selection and the target specification the grade designation serves. Technicians cut and stress-relief anneal the strip specimens and mount them in the Epstein or single sheet tester. The tester applies the stated peak induction and frequency and records the resulting core loss. Analysts then compare the recorded value against the core-loss-type limits and compile the specimen’s grade designation report.

Common Challenges and Troubleshooting in ASTM A664

Common problems and challenges include inconsistent specimen cutting direction, a key issue in core-loss measurement: strips cut off the rolling direction distort the measured value and skew the resulting grade designation. Residual stress from cutting and incomplete stress-relief annealing likewise affect results. Technicians address these issues by cutting specimens precisely parallel to the rolling direction, applying complete stress-relief annealing, and calibrating the core-loss measurement system regularly.

• Analysts report the specific core loss in watts per kilogram (W/kg). For example, a reference value of 0.940 W/lb corresponds to approximately 2.07 W/kg, calculated as 0.940 × 2.2046 = 2.07 W/kg.
• Analysts assign a six-character core-loss-type designation. For example, 35H094 identifies a nominal thickness of 0.35 mm because 35 ÷ 100 = 0.35 mm; the letter H identifies the applicable material and testing category, while 094 represents a reference maximum core loss of 0.940 W/lb.
• Engineers compare the measured core loss with the specified maximum value. For example, if the measured result is 1.95 W/kg and the specified maximum is 2.07 W/kg, then 1.95 ≤ 2.07 W/kg, indicating that the specimen satisfies the core-loss limit.
• Analysts document the magnetic test conditions with the result. For an H designation, the applicable reference condition is 1.7 T (17 kG) at 60 Hz; therefore, a result may be recorded as 1.95 W/kg at 1.7 T and 60 Hz for comparison with the applicable grade limit.

Link to ASTM A664