High Mn Steel roller

High chromium cast iron roller production process

一、高鉻鑄鐵輥套離心鑄造特點

The characteristics of High chromium cast iron roller by centrifugal casting.  

1 、采用離心雙金屬復合鑄造工藝。

  Using bi-metal composite centrifugal casting technology.

2 、離心鑄造利用離心力無氣孔、無夾雜。

  The centrifugal casting without pores and inclusions by using centrifugal force.

3 、金屬模具快速降溫金屬組織致密，提高耐磨性。

  Fast cooling metal mold making the casting have a compact microstructure to improve wear resistance.

4 、輥套外層高鉻鑄鐵，內層我們采用合金球鐵或合金鋼 ( 具有很高的強度和韌性）。

  Using high chromium cast iron(Cr17NiMo,Cr18Ni2,etc) to the out layer of roller, using alloy ductile iron like GGG400 etc or alloy steel like 35CrNiMo etc at inner layer (with high strength and toughness).

5 、根據使用要求，設計了合理的使用層厚度，減少了合金用量，降低了成本。

By reasonable wear resistant layer thickness design according to client’s requirement to reduce the dosage of alloy and the cost.

二、生產流程 The production process.

  1 ．熔煉 Smelting.

外層鋼水采用 P 、 S 含量≤ 0.02% 廢鋼及各種合金混合加熱熔化，爐前成分調整合格，過程中對鋼水進行脫氧保護。

The molten steel (P and S with content of ≤ 0.02%)for the outside layer add various kinds of alloy for mixed melting, making bath analysis to certified composition, together with deoxidization protection in the process of melting.

2 ．澆鑄 Casting pouring

根據輥套尺寸及鋼水重量選擇合適的離心機轉速。鑄型選用灰鑄鐵或鑄鋼材質，與鋼水接觸部位噴一定厚度的耐火涂料。嚴格控制鑄型內的清潔，無雜質，保證鑄件質量。輥套采用分層澆鑄：分別為外層、過渡層及內層，根據事先制定好工藝執行，外層選擇合適澆注溫度，間隔一段時間，澆鑄過渡層，保證外層與過渡層具有良好的復合狀態，同樣間隔一段時間澆鑄內層。待內、外層鋼水全部澆鑄完畢，等待輥套凝固成型后脫模，脫模后執行退火程序。

According to the roller size and weight to choose the appropriate centrifuges. Cast moulds choose grey cast iron or cast steel material, spraying a certain thickness of refractory coating. To control the cleanness inside the mold strictly, inclusion-free, to ensure the quality of castings. Roller shell use layered casting: outer layer, transition layer and inner layer, pouring according to the process setting in advance. The outer select proper pouring temperature, after interval of time, pouring the transition layer, to ensure that the outer layer and transition layer have a good composite state, after a interval time again, pouring the inner layer. Stay all inner and outer molten steel pouring out, waiting for the roller demoulding after coagulation casting, after demoulding, adopt the annealing process.

3. 熱處理 Heat treatment

   輥套采用退火、淬火、回火熱處理工藝。工件脫型后直接入窯進行退火，退火后粗加工，然后進行淬火，采用多次回火工藝，徹底消除鑄件內應力。

The roller use annealing, quenching and tempering heat treatment process. After demoulding, the roller casting will directly be put into the heat-treatment furnace for annealing, after that, take rough machining, and then quenching, several times with tempering process to eliminate the internal stress of castings thoroughly.