Recently, the world’s first cast QT900-2 high strength and high rigidity ductile iron cylinder successfully poured in Guangxi Yuchai Casting Co., LTD., from the cylinder blank surface quality, body anatomy and body performance test results, are better than the original cylinder block, weight also reduced by 30%.
The main difficulties in the production of nodular cast iron cylinder block lie in the complex structure of parts and the large difference of wall thickness. Because nodular cast iron is a paste solidification characteristic, it is difficult to achieve feeding through the conventional feeding process, the cylinder block is very easy to produce a large number of shrinkage holes and shrinkage problems, it is difficult to completely solve with the conventional process.
On the basis of successfully producing 3mm high-strength thin-walled flywheel shell replacement aluminum by using iron-type sand coating process, the casting QT900-2 material process was adopted to adjust and optimize the original cylinder block casting system, easy to produce shrinkage parts, sand coating thickness, iron type thickness and melting and many other process parameters, and achieved complete success. At present, the process material has been applied in the flywheel shell, crankshaft, bearing cover, robot reducer and other shaft and shell castings, and achieved good results.
At present, the material of commercial diesel engine cylinder block is developing towards vermicular iron material. However, vermicular iron material has some characteristics, such as low yield strength, large difference in energy of different creep rates, easy to produce stress and need structural strength to guarantee, which leads to many difficulties in realizing lightweight with vermicular iron.
At present, the material of commercial diesel engine cylinder block is developing towards vermicular iron material. However, vermicular iron material has some characteristics, such as low yield strength, large difference in energy of different creep rates, easy to produce stress and need structural strength to guarantee, which leads to many difficulties in realizing lightweight with vermicular iron.
The yield strength of this kind of high strength and high rigidity ductile iron is 114% higher than RUT400, and the elastic modulus is 13% higher. It is a new lightweight material for cylinder block. According to estimates, if applied to the heaviest engine cylinder block, is expected to reduce the weight of 100 kilograms, at the same time, the engine upgrade cylinder expansion becomes very easy, and can eliminate the gas engine, hydrogen engine knock caused by cylinder cracking problem, in Yuchai engine application of more than 11 liters displacement will be able to better help customers to achieve business value, It has great economic and social benefits.
