48MnV nitrogenous steel and nitrogen adding process thereof

Abstract

The invention belongs to the field of metallurgy and relates to 48MnV nitrogenous steel and a nitrogen adding process thereof. The 48MnV nitrogenous steel comprises the following components: 0.45-0.51% of C, 0.17-0.37% of Si, 1.00-1.20% of Mn, 0.06-0.11% of V, 0.000-0.025% of Ti, 0.05-0.25% of Cr, 0.00-0.06% of Mo, 0.00-0.06% of Ni, 0.00-0.20% of Cu, 0.0080-0.0150% of N, at most 0.035% of P, at most 0.035% of S, at most 0.020% of O, 0.087-0.097% of Ceq and the balance of Fe and impurities; and the nitrogen adding process is carried out while the N content is controlled to be 0.0080-0.0150%, preferably 0.0090-0.0120%, wherein the target value is 0.0110%, and a manganese nitride iron wire is fed into the steel according to the calculated quantity in one step after a vacuum process is completed. By changing the pre-vacuum nitrogen adding and alloying into the post-vacuum nitrogen adding and alloying, the invention changes the technological process of pre-vacuum nitrogen alloying and post-vacuum slight nitrogen regulation in the metallurgy field, thereby enabling the 48MnV nitrogenous steel to obtain good comprehensive mechanical properties, and improving the strength and toughness.

Description

technical field [0001] The invention belongs to the field of metallurgy and relates to a process for adding nitrogen to nitrogen-containing steel, in particular to a 48MnV nitrogen-containing steel and a process for adding nitrogen to the steel. Background technique [0002] 48MnV nitrogen-containing steel is non-quenched and tempered steel for hot forging, mainly used to manufacture diesel engine crankshafts. 48MnV steel is Mn-V series pearlite + ferrite non-quenched and tempered steel. Accurate control of the nitrogen content of high-grade nitrogen-containing steels such as 48mnV has always been a difficult problem in the metallurgical field. Although there are many ways to control the nitrogen content of steel, blowing nitrogen into the molten steel can be said to be the most economical and easiest method, but the premise of this method is that there is a large amount of nitrogen-fixing elements in the molten steel. For 48MnV steel, we have strictly controlled C, Mn, Cr,...

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Problems solved by technology

[0003] The nitrogen-increasing method currently adopted in the metallurgical field of 48MnV nitrogen-containing steel is to add manganese nitride, chromium nitride, vanadium nitride and other ferroalloys into the furnace, but this method is to increase nitrogen after tapping before vacuum, and the specific process is vacuum It was realized by adding manganese nitride and blowing nitrogen into the steel at the LF station before. However, after vacuum degassing, the nitrogen often returns to the nitrogen content level when no nitrogen was added before the vacuum, so it has to be vacuumed in the VD furnace. Adding the same amount of manganese nitride will cause waste of nitrogen-containing alloys. If manganese and chromium are not properly controlled, the consequences will be very serious. When the N content is low and Cr or Mn has reached the target value, adding alloys will cause It causes Cr or Mn to exceed the target value more, and this kind of N-containing steel is basically a narrow composition control steel, which is generally controlled strictly according to the point composition. Once the N-containing alloy is added, it is basically difficult to achieve the point composition control target. The use of users has a certain impact

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