Low-chromium stainless steel heat treatment method

Abstract

The present application belongs to the technical field of stainless steel, and relates to a low-chromium stainless steel heat treatment method, which comprises the following steps: (1) determining the optimal heat treatment temperature of a low-chromium stainless steel hot-rolled steel coil with an oxide skin; (2) pickling the low-chromium stainless steel hot-rolled steel coil with the oxide skin; (3) placing the pickled low-chromium stainless steel hot-rolled steel coil into a continuous annealing furnace for heat treatment, wherein the working temperature of the continuous annealing furnace is 50-60 DEG C higher than the optimal heat treatment temperature; and (4) cooling to room temperature. Through the acid pickling pretreatment of the steel coil, the heat absorption capacity of the steel coil is reduced, the heat treatment temperature of the continuous line is increased by 50-60 DEG C, the heat treatment temperature is in the normal working temperature range of the continuous line, and the problem that low-chromium stainless steel with a low heat treatment temperature cannot be heat treated on a conventional continuous annealing line is effectively solved.

Claims

1. A heat treatment method for low-chromium stainless steel, characterized in that, Comprising: (1) Determining the optimal heat treatment temperature T of the hot-rolled low-chromium stainless steel coil with mill scale; (2) Pickling the hot-rolled low-chromium stainless steel coil with mill scale; (3) Putting the pickled hot-rolled low-chromium stainless steel coil into a continuous annealing furnace for heat treatment, wherein the working temperature of the continuous annealing furnace is 50 - 60°C higher than the optimal heat treatment temperature T; (4) Cooling to room temperature; Wherein, the heat treatment method is applicable to the case where T < the lowest temperature that the continuous annealing line can stably control ≤ T + 60°C.

2. The heat treatment method for low-chromium stainless steel according to claim 1, characterized in that, The determination of the optimal heat treatment temperature includes: (1) Sampling from the hot-rolled low-chromium stainless steel coil with mill scale to be treated; (2) Conducting heat treatment tests in the laboratory according to the heat treatment time corresponding to 1 - 3 minutes per millimeter thickness of the steel plate and air cooling; (3) Testing the properties and / or microstructure of the heat-treated samples; (4) Determining the optimal heat treatment temperature according to the results.

3. The heat treatment method for low-chromium stainless steel according to claim 2, characterized in that, When the continuous annealing furnace conducts heat treatment, the heat treatment time corresponding to each millimeter thickness of the steel plate is consistent with the corresponding state of the heat treatment test in the laboratory.

4. The heat treatment method for low-chromium stainless steel according to claim 1, characterized in that, The optimal heat treatment temperature T is the average temperature of the furnace chamber corresponding to the space within ≤ 30 cm from the sample.

5. The heat treatment method for low-chromium stainless steel according to claim 1, characterized in that, The cooling to room temperature includes: cooling to room temperature by air or water or a mixture of air and water.

6. The heat treatment method for low-chromium stainless steel according to claim 1, characterized in that, By weight percentage, the low-chromium stainless steel comprises: 0 < C ≤ 0.15%, 0 < Si ≤ 1.0%, 0 < Mn ≤ 3.0%, 0 < P ≤ 0.045%, 0 < S ≤ 0.045%, 0 < N ≤ 0.03%, 10.5% < Cr ≤ 15%, 0 < Ni ≤ 1.0%, and the balance is Fe and inevitable impurities.

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