4.2 Classification of Tests 4.2.1 Acceptance Tests The following requirements are acceptance tests and shall be performed on each heat or lot as applicable. 4.2.1.1 Composition (3.1) of each heat. 4.2.1.2 Hydrogen content (3.1) and surface contamination (3.5.1.3) of each lot in the delivered condition. 4.2.1.3 Tensile properties (3.5.1.1) and microstructure (3.5.1.2) of each lot after solution and precipitation heat treatment. 4.2.1.4 Tolerances (3.7) of each lot of bars and wire. 4.2.2 Periodic Tests Ability of forging stock (3.5.2) and stock for flash welded rings (3.5.3) to develop required properties, and grain flow of dieforgings (3.6.1) are periodic tests and shall be performed at a frequency selected by the vendor unless frequency of testing is specified by purchaser. 4.3 Sampling and Testing Shall be in accordance with AMS2368 and as follows; a lot shall be all product of the same nominal size from the same heat processed at the same time and annealed in the same heat treat batch: 4.3.1 For Acceptance Tests 4.3.1.1 Composition One sample from each heat, except that for hydrogen determination one sample from each lot obtained after thermal and chemical processing has been completed. 4.3.1.2 Tensile Properties One or more samples from bars, wire, and flash welded rings from each lot. The number, location, and orientation of samples from each lot of forgings shall be as agreed upon by purchaser and vendor. 4.3.1.2.1 Specimens from flash welded rings shall be cut from parent metal not including the weld-heat-affected zone. 4.3.1.3 Microstructure and Surface Contamination One or more specimens from each lot shall be prepared metallographically for microstructure and surface examination.