This standard specifies the requirements, test methods, inspection rules, marking, packaging, transportation, storage and order (or contract) content of ammonium paratungstate.
This standard is applicable to ammonium paratungstate for powder metallurgy products such as hard alloy and tungsten products.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 1479 Metallic Powders - Determination of Apparent Density - Part 1: Funnel Method
GB/T 3249 Standard Method for Determination of Particle Size of Powders of Refractory Metals And Compounds - Fisher method
GB/T 4324 (All Parts) Methods for Chemical Analysis of Tungsten
GB/T 5060 Metallic Powders; Determination Of Apparent Density - Part 2: Scott Volumeter Method
GB/T 5314 Powders for Powder Metallurgical Purposes - Sampling
3 Requirements
3.1 Product classification
According to different requirements for impurity contents in chemical component, the product is classified into two designations of APT-0 and APT-1.
