GB/T 26297.3-2010Sampling of carbonaceous materials used for aluminium production -- Part 3: Prebaked blocks (English PDF)

2.1 General

As long as the parties have agreed in accordance with acceptable quality level (AQL) to determine the sampling plan can be sampled from a variety of parties in this section Select a case recognized by all concerned as a program implementation plan. Interested parties should be measured to determine the properties (such as density and Resistivity), so that the sampling plan in order to achieve the ultimate goal of providing the most representative samples for subsequent performance testing.

When the parties changed on sampling programs (see Table 1, Table 2, Table 3 and Table 4) as recommended values \u200b\u200bgiven in this part of step Procedure still applies.

When n/N is less than 10%, the efficiency of the sampling scheme depends entirely on the number of (n, ie sample size) sampling units, and with the batch the number of size (N) irrelevant. In practice, the required representation on the basis of Table 1, Table 2, Table 3 and Table 4 to select the sample size (n).

If experience shows that the quality of products in line with the production side of protocol requirements, and have the same quality of each batch of product has been ongoing compliance Contract, you can choose a lower-cost sampling program, using a smaller sampling units (n).

If subsequent experience has shown that time by requiring prior acceptance has been reached, the product quality of the production side does not meet these requirements, it certainly to be more efficient to re-use the original sampling plan.

In addition, it can also be used to detect the average value (within the allowable deviation range) instead of the acceptable quality level (AQLs) developed sampling plan.

In developing the sampling program is recommended to use mathematical or statistical quality control map as processing tools.

2.2 Sampling base

Both parties shall determine by sampling base. Sampling units should base the anode blocks.

2.3 Sampling plan based on the development of acceptable quality level (AQL)

Before sampling plan based on these tables to determine, you must first determine the following parameters.

a) acceptable quality level, is considered the average minimum acceptable quality level.

b) Whether the use of a routine examination or the use of tightened inspection, the final test results are extracted by a few batches of the aliquot Analysis of the results of the decision. 2.5.2 in accordance with the principles given in choosing a routine examination or the use of tightened inspection.

c) batch size may be the same production batch number of products that can also be a continuous total monthly production or delivery.

2.4 in accordance with the acceptable quality level (AQL) sampling plan implementation

2.4.1 Table 1 gives the recommended value of 2.3 appropriate three parameters. If necessary, both supply and demand values \u200b\u200bcan be determined by mutual agreement Instead of these recommendations, but it must be noted in the sampling report.