GB/T 4236-84 – Steel Sulfur Print Inspection Method

This standard specifies the sulfur print inspection method for steel, which is used to determine the distribution and degree of sulfur segregation in steel.

1. Scope

This standard specifies the sulfur print inspection method for steel. This method is applicable to the inspection of sulfur segregation in various steel products.

2. Specimen Preparation

The specimen size shall generally not exceed 100mm x 100mm. The inspection surface shall be machined with a surface roughness Ra not greater than 2.5um. The inspection surface shall be free from stains and scratches.

3. Preparation of Sulfuric Acid Solution

• Sulfuric acid solution concentration: 5% by volume
• Use chemically pure sulfuric acid and distilled water for preparation
• Solution temperature shall be maintained at 16-25 degrees C

4. Test Procedure

1. Soak photographic paper in the sulfuric acid solution, then apply it to the specimen inspection surface.
2. Press gently with a glass plate to eliminate air bubbles, and maintain contact for 1-3 minutes.
3. Remove the photographic paper, then rinse with clean water, fix, wash again, and dry.

5. Evaluation of Results

Black or brown spots on the sulfur print image indicate the locations of sulfur segregation. The size and density of the spots reflect the sulfur content and the degree of segregation. Evaluate according to the standard reference images.

6. Safety Precautions

• Conduct the operation in a fume hood
• Acid solution must not come into contact with skin
• Discarded acid solution shall be neutralized before disposal

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Original Standard PDF (Chinese Version)

Download the original GB/T 4236-84 standard document in Chinese:

Download GBT_4236-84_Steel_Sulfur_Print_Inspection_Method.pdf