ASTM A48 class 25 is a material grade of gray cast iron in
Mechanical Properties of A48 Class 25 Cast Iron:
Its minimum tensile strength is 172 Mpa. The gray cast iron is brittle, so there is no requirements to yield strength and elongation. Its hardness range is BH 170-229.
Although gray iron has bad tensile strength, but their production costs are low, and easily manufactured, moreover, this material has good Vibration reduction, abrasive resistance, and low notch sensitivity. In addition, they could be machined easily.
Chemical Composition of A48 Class 25 Cast Iron:
C%: 3.20-3.50, Si%: 1.60-2.40, Mn%: 0.60-0.90, P% ≤ 0.20, S% ≤ 0.15, CE: 4.00-4.25.
We have talked about this issue for many times in the past. In all international standards, there is no compulsive stipulation to the chemical composition range. This is very different with cast steel. As for gray iron and ductile iron, the chemical composition is just for reference. The iron foundries could adjust the composition as long as the mechanical properties could meet the requirements.
Heat Treatment of ASTM A48 Class 25 Gray Iron:
The heat treatment can not change the structure of graphite, so can not improve their mechanical properties, however, the annealing treatment could reduce the internal force, and chilling organization, stable the deformation, and improve the abrasive resistance. However, the heat treatment will cause more production costs, so most of grey iron castings will not be heat treated, unless some special application.
Main Application of ASTM A48 Class 25 Gray Iron:
Class 25 gray iron could be used to produce casting parts as machine base, frames, supports, cases, machine body, bearing support, foundation plates, belt pulley, end caps, pump bodies, valve bodies, pipe fittings, fly wheels, gears etc.
The followings are some casting products manufactured by our iron foundry.