Ammonium Paratungstate National Standard
Ammonium paratungstate national standard: GB/T 10116-2007
The standard stipulates the requirement, testing method, testing rule, symbol, packing, transportation, storage, purchase order and contract of APT. The standard is suitable for produce tungsten carbide and tungsten products using ammonium paratungstate.
The following terms being referred has become the terms of this standard. The standard noted with date which may be adjusted thereafter does not apply to this standard. However, both parties can discuss whether to adopt these modified standards or not. Referred documents without date can be applied to this standard if there is any modification.
GB/T 1479 Testing for metal powder apparent density, part one, funnel method
GB/T 3249 Testing method for refractory metal and compounds powder: Fsss method
GB/T 4324 Chemical analysis method of tungsten
GB/T 5314 Sampling method of powder metallurgy method, part two, scott capacity meter method
GB/T 5060 Apparent density testing method of metal powder
3.1 Product range
According to different impurity content requirement of chemical specification, it can be divided into APT-0 and APT-1.
3.2 Chemical Specification
Chemical content should be complied to table 1.
3.3 Grain Size
Grain size of product should be complied to table 2.
3.4 Apparent Density
Apparent density and other physical property should be negotiated by both supplier and demander.
Product should be through mesh of 250um.
Produce should be white crystalline, color should be accordance, there is no visual inclusions in product.
4. Testing Method
4.1 Chemical analysis of tungsten powder should follow GB/T 4324.
4.2 Average FSSS size of tungsten powder follows GB/T 3249.
4.3 Apparent density should follow GB/T or GB/T 5060.
4.4 Sieving of product is determined by supplier and demander.
4.6 Appearance of tungsten powder is checked by visual.
5 Testing Rules
5.1 Inspection and acceptance
5.1.1 Product is tested by quality assurance department of supplier to insure the product is complied to the standard, the product quality certificate needed to be completed.
5.1.2 Demander can inspect the product according to this standard, if the testing result is differ from the standard, then supplier should bring it up within one month to the seller and negotiated by both party.If arbitration is needed, sampling should be taken by both party.
5.2 Lot grouping
Product should be examined by batch. Every lot is composited by the tungsten carbide powder of same grade, quantity is negotiated by both party.
5.3 Testing Items
Testing items and sample quantity follow table 3.
|Inspection Item||Sample||Article Ref.||Testing Method Ref.|
|Chemical Content||GB/T 5314||3.2||4.1|
|Grain Size, Apparent Density||GB/T 5314||3.3、3.4||4.2、4.3|
Sample should be complied to GB/T 5314.
5.5 Testing result judgement
5.5.1 If there is one item of the product is disqualification, then double amount of sample needs to be tested. If it is still disqualification, then this batch is unqualified.
5.5.2 If one of the grain size, specific surface area, total carbon, free carbon, chemical carbon and oxygen content of the product is unqualified, then double amount of sample needs to be tested. If it is still disqualification, then this batch is unqualified.
5.5.3 Appearance of product is checked by barrel, unqualified barrrel can be scrapped.
5.5.4 When sieving of FWP-1 is unqualified, then double amount of sample needs to be tested. If it is still disqualification, then this batch is unqualified.
6 Mark, packing, transport and storage.
6.1 Packing of product adopt iron drums with double inner sealed polyethylene plastic bag, weight of each bag is determines by both parties.
6.2 Outter packing of product should mark: supplier's name, product name, grade, specification, log number, net weight, also marks of DAMP PROOF, UPSIDE and so on.
6.3 Quality certificate should be included in every batch of product. It should includes:
a) Supplier name, address, postcode;
b) Product name, grade;
c) Batch number;
d) Weight (net weight and gross weight);
e) Standard number；
f) Test result and seal of quality inspection department;
g) Inspector ID;
h) Inspecting date.
7.Purchase Order and Contract
a) Product name;
b) Product grade, specification;
c) Technical requirement;
d) Net weight;
e) National standard serial number;
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