Definition and classification of ferrochromium

Ferrochromium is an iron alloy composed of chromium and iron. It is an important alloy additive in steelmaking.

According to different carbon content, ferrochromium is divided into high carbon ferrochromium (carbon content of 4~8%), medium carbon ferrochromium (carbon content of 0.5~4%), low carbon ferrochromium (carbon content of 0.15~0.50%), Micro-carbon ferrochromium (with carbon content of 0.06%), ultra-fine carbon ferrochromium (with carbon content of less than 0.03%), as well as silicon-chromium alloy, ferro-chromium nitride, etc.

The lower the carbon content of ferrochromium, the more difficult it is to smelt, the power consumption is also large, and the cost is high. Ferrochromium with a carbon content of less than 2% is suitable for smelting stainless steel, acid-resistant steel and other low-carbon chromium steels. Ferrochromium with a carbon content of more than 4% is often used to make ball bearing steel and steel for auto parts. Ferrochromium with a chromium content of about 5% can be used as a chromium addition agent for alloy transfer iron.

An iron alloy with chromium and iron as the main components. It is one of the main alloying agents used in the iron and steel industry. In addition to the main components of chromium and iron, it also contains impurities such as carbon, silicon, sulfur, and phosphorus. Ferrochromium contains 55% to 75% chromium, and is divided into high carbon (4% to 10% C), medium carbon (0.5% to 4% C), low carbon (>0.15% to 0.5% C) and low carbon (>0.15% to 0.5% C) according to the carbon content. Micro-carbon (≤0.15%C) ferrochromium. High carbon ferrochromium is also called carbon ferrochromium, and medium, low and micro-carbon ferrochromium is also called refined ferrochromium. A high-carbon ferrochromium produced from chrome ore with a low chromium-to-iron ratio, containing 50% to 55% of Cr is called charge grade ferrochromium, and nitrogen-containing ferrochromium containing N2% to 10% is used as a nitrogen alloying agent. Also known as ferrochromium nitride.

Ferrochrome is divided into high carbon ferrochrome according to different carbon content, including charging grade ferrochrome (C≦10%), medium carbon ferrochrome (C≦4.0%), low carbon ferrochrome (C≦0.5%), micro carbon Ferrochrome (C≦0.15%), etc. Commonly used are silicon-chromium alloy, ferrochromium nitride and so on. Ferrochromium is mainly used as an alloying additive in steelmaking, and in the past it was added at the later stage of refining in steelmaking. The smelting of stainless steel and other low-carbon steels requires the use of low and micro-carbon ferrochromium, so the production of refined ferrochromium was once developed on a large scale. Due to the improvement of the steelmaking process, when using the AOD method (see out-of-furnace refining) to produce stainless steel and other steel grades, carbon ferrochrome (mainly charging grade ferrochrome) is used to charge the furnace, so it is only necessary to add low and micro chrome in the later stage. Carbon ferrochromium adjusts the composition, so ferrochromium production is refining carbon ferrochromium.