Process

Manhole cover

A

stringent requirements for chemical composition, carbon and silicon content of the molten iron of the original claim is higher than gray iron, ductile iron to reduce the content of manganese, phosphorus, sulfur,

B

the temperature of molten iron released higher than gray cast iron, to compensate for the ball, gave birth to loss treatment temperature of molten iron

C

Spheroidized, which was added to the iron ball agent

D

by adding inoculant inoculating

E

ductile illiquid, a larger contraction, and therefore requires a higher temperature and larger casting gating system size, reasonable application riser, cold iron, using the principle of directional solidification

F

heat-treated ductile iron manhole covers Specifications: ductile iron manhole covers and gray cast iron covers are the same size, the material is different, to introduce you ductile covers "chemical and physical features of the new manhole covers using ductile cast QT500-7 cast light weight, high strength, toughness, corrosion resistance, fatigue resistance, suitable with the same cost and size of gray cast iron manhole covers and light weight compared to 40% to 50% higher strength compared to 40% to 50% higher than the old gray cast iron covers. The old gray cast iron covers brittle easily broken. Now ductile and gray iron products of chemical composition, physical properties from the above compare the chemical composition and physical properties of ductile iron in terms of data comparison drawn tensile strength, elongation, yield strength and ultimate load indenter decisive indicators of several materials much higher than gray cast iron chemical composition of various kinds of data much more reasonable than gray cast iron.