The principle of alloy configuration in the existing technology of medium carbon ferromanganese is: for all steel types, judge that the upper limit of phosphorus of the steel is ≤0.020%, judge that the upper limit of mn of the steel is ≥0.8%, all use low phosphorus medium carbon ferromanganese with mn, and judge that the carbon of the steel is Mid-range 0% At that time, all carbon ferrochromes were used with cr. In this way, due to the wide range of judgment conditions, the cost of adding alloys is high. In addition, judging steel means that the chemical composition and process of the steel meet the technical requirements and can be judged as a qualified product.
In order to reduce the cost of alloy addition in low phosphorus, carbon ferromanganese provides a steelmaking alloy addition method: judge the upper limit of steel according to the steel type and select the metal mix mn; if mn reaches the target value and si does not reach the target value, then Use ferrosilicon and si to match the target value; if si reaches the target value and mn does not reach the target value, determine whether the carbon mid-range limit of the steel is ≤0.10%. If so, use carbon ferromanganese in low phosphorus to match mn to the target value. value, otherwise use carbon ferromanganese in low phosphorus to match mn to the target value; if it is judged that the steel C mid-limit, medium carbon ferromanganese is judged to be ≤0.15%, use medium carbon ferrochrome to match cr to the target value; If it is 0.15% 5.% and it is judged that the steel cr limit is ≥ 1.0%, first, use an agreed amount of medium carbon ferrochrome to equip it with cr. After configuration, if cr does not reach the target value, use high carbon ferrochrome to equip cr to the target value; if it is judged that the middle limit of steel C is ≥0.25%, use high carbon ferrochrome to equip cr to the target value.
If the steel type determines that the upper limit of steel is ≤ 0.015%, all use low phosphorus, medium carbon ferromanganese to match mn to the target value; if the steel type determines that the upper limit of steel is ≤ 0.020% and the upper limit of steel mn is determined to be ≥ 1.0%, use the preset amount first Low phosphorus carbon ferromanganese is matched with mn. If mn does not reach the target value after configuration, silicon-manganese alloy is used to match mn; silicon-manganese alloy is used to match mn. The preset quantity is up to 1 ton. The target value is: if the lower limit of steel is 0, the target value of the element is 0; if the upper limit of steel - the lower limit of steel ≤ 0.12%, the target value of the element is the middle limit of steel minus 0.02%; otherwise, medium carbon The target value of ferromanganese element is 0.08% less than the limit for judging steel.
If the middle limit of steel si is judged to be 0.1% to 0.2%, the target value of si is not less than 0.16%; if the middle limit of steel mn is judged to be 0.15% to 0.24%, the target value of mn is not less than 0.17%. Compared with the existing technology, the beneficial effect is to select different alloys according to different judgment conditions and reduce the use of high-cost alloys to meet the need for cost reduction. In addition, specific element addition target values are set, which not only allows the steel to meet quality requirements, but also keeps the cost relatively low.
