| Hollow bricks are commonly used in the construction industry as the main wall material in recent years, and become an ideal filling material of frame construction buildings, because of its high strength, good soundproof performance, environmental protection & less pollution. Now it has become the first recommended project by our National Building Department.Firstly, this article summarized production raw materials, equipments and work flow of hollow brick. It was pointed out that the main problems and difficulties existed in the process of hollow brick producing after being comparative analysis the hollow bricks'production conditions between our country and other countries. The research of this paper was mainly included the improvements of hollow brick forming dies.The core tools of the hollow brick are the key components of the extrusion forming mold. Comparing with other parts of the mold, the core tools, especially core heads and sticks, suffered from more severe abrasion. Now the main connection of hollow bricks is welding with some wearable materials.The second part proposed the three choices of experimental materials, related laboratory equipment, experimental process and parameter settings in this paper.The third part pointed out the problems of core tools by the original core tools structure, namely the whole tools short life caused by limitations of the contradiction of welding structure. So we improved the structure connection from welding connection to machinery connection, at the same time the core block was designed to inblock cast.The fourth part presented optimization of material selection of every part of the core tool and follow-up technological processing proposal of these materials. Inblock cast of the core block selected ZG50SiMnCrNiMo, using the Cr12TD vanadizing treatment and strengthening and toughening instead of core head and stick which is made of 20Mn and with better performance but less wearing ability; and the core stick made of 50CrVA steel could also meet the performance requirement of both plastic ductility and wear resistance. The fifth part introduced the preparation technology of the new designed core tools, and this technology was mainly to deal the pre-processing core head and stick with TD vanadizing treatment(borax salt bath 960℃*4h).,then carry on the corresponding follow-up treatment, so as to get each part of core tool which is satisfy a requirement.At last,assess the new core tools of the hollow brick by relative wear resistanceεevluation. The result of the test found that in the situation of sand slurry abrasion,comparing with 20Mn steel(untreatedε=1),Cr12 as TD with vanadium(ε=6.45)and 20Mn plating with chrome(ε=5.19) performance excellent wear resistance;but YT14 hard alloy (ε=1.55)and 95 Alumina ceramics(ε=0.93)had little contribution to improve wear resistance.The results of the research in this paper showed that because of core tools' mechanical assembly replace welding structure brings two advantages.On one hand it permits flexible choice materials with excellent wear resistance which is good to surface modification and strengthening and toughening.On the other hand core sticks can be replaceed after wear away,in favor of efficiency production of the hollow bricks extrusion.The improved core tools which have processed with TD salt-bath treatment and heat treatment have much effect on improving brick mould'service life.
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