GB/T 12626.3-2009Hardboard - Part 3: Sampling and measurement of test pieces (English PDF)

Foreword

GB/T 12626 "wet hardboard" is divided into nine sections.

--- Part 1. Definitions and classification;

--- Part 2. Common requirements for all board types;

--- Part 3. Specimen Samples and measurements;

--- Part 4. General plate for use in dry conditions;

--- Part 5. Common plate under wet conditions of use;

--- Part 6. ordinary plate under high humidity conditions of use; Ordinary plate under outdoor conditions of use;.

--- Part 8. under dry conditions using carrier plate;

--- Part 9. humid conditions bearing plate used. This section GB/T Part of 312,626. This part is GB/T 12626.3-1990 "hardboard" amendments. This Part replaces GB/T 12626.3-1990. This section compared with the GB/T 12626.3-1990 main technical changes are as follows:

--- Remove the sawing requires absorption of the specimen;

--- Increased 24h thickness swelling, 2h boiled in the boiling water bond strength after 70 °C water immersion MOR specimens sawn Claim. This part by the State Forestry Administration. This part of the National Standardization Technical Committee centralized wood-based panels. This section is responsible for drafting units. China Forestry Science Institute of Wood Industry. Participated in the drafting of this section. Dunhua Danfeng forestry fiberboard limited liability company, Yichun City, Heilongjiang Province friendship and fibreboard plant in Henan Province Ltd. Xinxiang Tyrone system board. The main drafters of this section. Fan Yang, Qu Yan Chun, Wang new, Rencheng Bin, Debris, Pan Yulin. This section was first released in October 1980, in December 1990 the first amendment, this is the second revision. Wet hardboard Part 3. Specimen Samples and measurements

1 Scope

Part 3 of China's series on wet process hardboard, covering the sampling of boards and the cutting and measurement of the test pieces taken from them. It specifies the sampling of wet process hardboard and the preparation and measurement of the test pieces. It is the part the whole series depends on and the one nobody reads, which is the usual fate of sampling standards - and the usual reason results are disputed. A board is not uniform. It is made continuously on a machine and its density, thickness and moisture vary across the width of the mat and along its length, so a test piece cut from the edge of a board is not the same material as one cut from the middle, and a board taken from the start of a run is not the same as one from the end. If the sampling is not fixed, two laboratories testing the same consignment can reach opposite conclusions honestly. This part therefore sets how many boards are taken from a lot and which ones, where on each board the test pieces are cut from and in what orientation, how far from the edges they must be, the dimensions and the tolerances of the pieces themselves, and how they are conditioned before testing - which for a hygroscopic material is not a formality, since the mechanical properties of a fibre board change measurably with its moisture content. It then sets how the pieces are measured: the thickness, length and width, at which points and with what instrument, and how the values are combined. Issued on 30 September 2009 and in force since 1 December 2009, it replaces GB/T 12626.3-1990.

GB/T 12626 provisions of this part of the wet hardboard physical and mechanical properties of specimen sampling and sawing, specimen size measurements. This section applies to GB/T defined in

3.1 wet hardboard 12626.1-2009.

2 Normative references

The following documents contain provisions which, through reference

GB/T 12626 in this section constitute provisions of this section. For dated reference documents Member, all subsequent amendments (not including errata content) or revisions do not apply to this section, however, encouraged to reach under this section Parties to research agreement to use the latest versions of these documents. For undated reference documents, the latest versions apply to this section.

GB/T 17657 panels and veneer plywood physical and chemical performance test method

3 Specimen sampling and sawn

3.1 Specimen sampling Specimen sampling the finished store 24h later time.

3.2 specimen sawn

3.2.1 Interception of half a sheet for each test from the sheet, in accordance with regulations 1 interception 500mm × 500mm specimen. Millimeters Figure 1 a schematic cut sample

3.2.2 Preparation Referring to Figure 2 specimen, specimen size, and the numbering of Table 1. At least one specimen is cut from a side edge of the plate Sawing unit, the minimum distance between two specimens of the same test items should be 100mm.