Rules for inspecting ductile iron pipe fittings

Rules for inspection and acceptance of ductile iron pipe fittings
The inspection and acceptance of ductile iron pipe fittings are carried out by the supplier's technical quality supervision department.
The size, surface and coating quality of pipe fittings should be inspected piece by piece.
Batch rules
Pipe fittings should be inspected and accepted in batches. Each batch consists of a pipe fitting produced by the same furnace of molten iron and the same molding process.
Sample quantity
The size, surface and coating quality of ductile iron pipe fittings should be inspected piece by piece.
Take one sample from each heat for tensile testing. When the charge is changed, resampling should be carried out. The test results represent all pipe fittings produced after the charge is changed.
One hardness sample per heat.
Pipe fittings must be tested for hydraulic pressure one by one, and pipe fittings for gas transmission must be tested for air tightness one by one.
The weight of pipe fittings should be randomly checked, and one piece of the same type, the same batch, and the same specification should be randomly checked.
Inspection and Judgment Rules
If the initial tensile test fails, double the sample should be taken for re-inspection. If one sample fails as a result of the re-inspection, the entire batch shall not be delivered.
When ductile iron pipe fittings are supplied in the cast state, if the tensile test fails, the supplier can, with the consent of the purchaser, heat-treat the pipe fittings and the test blocks they represent and then re-accept them. If the test sample fails, the whole Delivery is not allowed in batches.