AS 1004.1-1998 pdf free.Surface plates for metrology – Part1:Cast iron.
This part of ISO 8512 specifies requirements for rectangular or square cast iron surface plates ranging from 160 mm x 100 mm to 2 500 mm x 1 600 mm, as preferred sizes, in four grades of accuracy 0, 1, 2 and 3.
This part of ISO 8512 applies to new cast iron surface plates, cast iron surface plates in use, and those reconditioned according to their grade.
4 Nomenclature
For the purposes of this part of ISO 8512, the nomenclature shown in figure 1 applies.
5 Material
Good quality, close-grained, plain cast iron or alloy cast iron at least equal to grade 250 of ISO 185 shall be used; the material shall be sound and free from blow holes and porous patches. Minor defects in working surfaces of grades 2 and 3 only may be repaired by plugging with material of composition, similar to that of the plate.
6 Stress relief
After being cast and rough machined, all plates grades 0 and 1 and of size up to and including 400 mm x 250 mm shall be given a suitable treatment to relieve internal stresses before being finished. It is strongly recommended that larger plates of all grades be stress-relieved by similar means; however, where facilities for this purpose are not available, such plates may be stabilized by natural ageing by agreement with the purchaser.
The manufacturer shall, on request, supply the purchaser with a statement of the stress-relieving process which the plate has received.
9 Finish of the working surface
The top (working surface) of grades 0 and 1 plates shall be finished by scraping or other process which results in a surface similar to that obtained by scraping. Grades 2 and 3 plates may be finished by the same processes or by machining.
The bearing area shall be not less than 20 % for grade 0, 15 % for grade 1 and 10 % for grades 2 and 3. High spots shall be uniformly distributed and the percentage of bearing area should not be so high as to cause wringing.