The material of Cast Iron Inspection Plate is high-strength cast iron Ht200-250 and the hardness of the working surface is HB 160-210. After artificial heat aging treatment( Artificial annealing temperature 600℃ to 700℃or 2-3 years natural aging) the internal stress was totally eliminated, so the surface plate have stable accuracy and good wear-resisting performance.
铸铁平台精度：按国家标准计量检定规程执行，分别为0，1，2，3级四个级别
The Cast Iron Surface Plate can be classified as Grade 0,1,2,3,4 according to the national standard metrological verification procedures
铸铁平台退火种类常见的T型槽铸铁平台[2]退火工艺有：再结晶铸铁平台退火，去应力铸铁平台退火，球化铸铁平台退火，完全铸铁平台退火等。铸铁平台退火的目的：主要是降低金属材料的硬度，提高塑性，以利切削加工或压力加工，减少残余应力，提高组织和成分的均匀化，或为后道热处理作好组织准备等。
There are many annealing type for Cast Iron Surface Plate, such as stress relief annealing, recrystallization annealing, spheroidizing annealing, full annealing, etc. The purpose of annealing process is to reduce the hardness of metal materials, to improve the plasticity, contributing to cutting and pressure machining process. It also can reduce the residual stress, improve the organization and composition of the homogenization.