Material selection of Dalian castings shall match casting materials according to service conditions. Mechanical properties, temperature and corrosion resistance of casting materials directly determine service life. Collect operating parameters including load, impact force, working temperature and contact medium before material selection, which serves as the foundation for material selection.
Grey cast iron is adopted for ordinary housings and bases under static load without severe impact. It features good vibration damping, excellent casting fluidity, easy forming and low machining cost, widely used for machine bases and counterweight boxes. Pay attention to service environment: grey cast iron tends to rust in humid conditions and requires anti-corrosion coating. For outdoor grey iron castings in Dalian’s coastal area, thicker anti-corrosion coating is needed to retard corrosion.
Ductile iron Dalian castings are used for workpieces under alternating load and impact, such as connecting rods, gears and pump bodies. Ductile iron combines strength and toughness with better fatigue resistance than grey cast iron and can bear certain impact loads. It is often used to replace small steel castings. Check nodularity and ensure elongation meets drawing requirements. Verify low-temperature impact properties for low-temperature service to prevent brittle fracture.
Cast steel Dalian castings are selected for heavy-load and high-impact conditions, e.g. crusher liners and mining wear-resistant parts. Cast steel has high strength and outstanding impact resistance. Carbon content of different grades can be adjusted to meet wear resistance or toughness requirements. High manganese steel castings suit components subjected to repeated impact abrasion; a hardened layer forms on the surface under impact to improve wear resistance. Ordinary carbon cast steel is for general structural load-bearing parts. Cast steel has large solidification shrinkage; riser design is required to reduce shrinkage cavities.
Stainless steel Dalian castings are used for environments with acid, alkali or salt spray. Many equipment components in coastal Dalian work in humid salt-laden atmosphere. 304 stainless steel castings fit weak corrosive media; 316 stainless steel castings with superior pitting resistance are selected for strong acid and alkali conditions. Control cooling rate during casting to reduce blowholes and intergranular corrosion. Stainless steel castings have moderate hardness and are not suitable for heavy abrasion without protection.
Aluminum alloy castings are used for thin-walled, complex-shaped Dalian castings requiring weight reduction. Lightweight and thermally conductive, they are ideal for heat dissipation components such as housings and cooling bases. Aluminum alloy castings have limited mechanical strength, unsuitable for heavy impact and high-temperature environments where strength drops sharply.
Besides load and medium, machinability shall also be considered. Grey cast iron is easy to machine, while stainless steel castings bring higher machining difficulty and tool consumption. Heat treatment can adjust mechanical properties of ductile iron and cast steel via quenching and tempering or normalizing.
Conduct material tests on samples or produce trial castings for simulated service tests before material confirmation. Take weld repair requirements into account: cast steel has better weldability while some cast irons are hard to weld. Apply surface treatment: sandblasting and coating are used for grey iron and cast steel castings deployed in coastal environments for corrosion protection.
Select proper materials for Dalian castings by comprehensively considering load, impact, working temperature, contact medium, machining requirements and local salt-spray humid climate in Dalian, so as to reduce failure risks from cracking, abrasion and corrosion and ensure long-term stable service of castings.
