Cast Iron Surface Plates

• Hardness between 170 to 220 BHN.
• Box type ribbing pattern.
• Inspection by high precision level or electronic level traceable to NABL.
• Stress relieved to relieve internal stresses.
• M.S. stands or C.I. columns with leveling facility can be supplied..
• All plates are provided with rexine protection cover
• Castings stress relieved to relieve internal stresses.
• Made from close-grained cast iron conforming to grade FG : 220,
• heavy ribbed and hardness between 180 HB to 210 HB
• Hand scraped surface finish

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.

After being cast and rough machined, all plates of grades O 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 tinished. H 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.

Cast iron surface plates shall be made with adequate ribbing and the total depth [i.e. the combined thickness of the top (working surface) and the depth of the framing] shall be such that when a concentrated load is applied about the centre of the plate, the loaded area shall not deflect below the remaining area of the plate by more than 1 pm/200 N. The limiting value for deflection applies to surface plates of size 400 mm x 250 mm and larger.