Stainless steel passivation process

Abstract

The invention relates to a stainless steel passivation process. The stainless steel passivation process comprises the following steps: mechanically polishing stainless steel; placing the stainless steel into a deoiling solution for soaking for 10-15min at normal temperature so as to remove oil stain on the surface of the stainless steel; further placing the stainless steel into an acid washing solution for soaking for 6-8min so as to remove oxide scales and corrosion products on the surface of the stainless steel; then placing the stainless steel into an electrolyte prepared by H3PO4, polyethylene glycol, H2SO4 and glucose, performing electrolysis for 6-7min at the temperature of 40-80 DEG C by adopting voltage of 6-8V, and washing the surface with deionized water to enable the surface to be smooth after the end of electrolysis; placing the stainless steel into a 5%-10% NaHCO3 solution for soaking for 3-6min at normal temperature to neutralize the residual electrolyte on the surface; placing the stainless steel into a passivation solution prepared by citric acid and acetic acid for soaking for 30-60min at room temperature; placing the stainless steel into a 5%-7% NaHCO3 solution for neutralizing for 3-5min at room temperature, and then completely washing with the deionized water; and drying.

Description

technical field

[0001] The invention belongs to a stainless steel surface treatment process, in particular to a stainless steel passivation process for improving the corrosion resistance of stainless steel through chemical method for stainless steel surface passivation treatment. technical background

[0002] The most important feature of stainless steel is corrosion resistance. In addition to the material itself, the performance of stainless steel is also related to the quality of passivation on the surface of stainless steel. If the passivation film is incomplete or defective, stainless steel will still be corroded. The passivation film of stainless steel is easily destroyed in many special cases, which will reduce the overall or local corrosion resistance of stainless steel, such as pollutants brought in during welding, forming, weld inspection, etc. The method of pickling and passivation is commonly used in engineering to maximize the corrosion resistance of stainless st...

Examples

Embodiment 1

[0023] A stainless steel passivation process is used to passivate 304 stainless steel, the steps are as follows:

[0024] Step 1. Mechanical polishing, polishing with 400, 600, and 800-grit sandpaper in turn.

[0025] Step 2. Degreasing, at room temperature, put the mechanically polished 304 stainless steel into 5g of Na 2 CO 3 , 3.75g of NaOH, 5g of Na 3 PO 4 , 2.5ml of OP-10, and 250ml of H 2 Soak in O for 10 minutes to remove oil stains on the surface of 304 stainless steel;

[0026] Step 3. Pickling, put the degreased 304 stainless steel into 75ml of H at normal temperature 3 PO 4 , 50ml of H 2 SO 4 , 100ml of H 2 Soak in the solution prepared by O for 6 minutes to remove the scale and rust on the surface of the stainless steel;

[0027] Step 4. electrolytic polishing, the H containing 600ml / L 3 PO 4 , 275ml / L H 2 SO 4 , 125ml / L H 2 The solution that the polyethylene glycol of 0, 8g / L, the glucose of 10g / L is formulated as electrolytic solution, adopts the v...

Embodiment 2

[0035] Adopt a stainless steel passivation process to passivate 316 stainless steel, the steps are as follows:

[0036] Step 1. Mechanical polishing, polishing with 400, 600, and 800-grit sandpaper in turn.

[0037] Step 2. Degreasing, at room temperature, put the mechanically polished 304 stainless steel into 5g of Na 2 CO 3 , 3.75g of NaOH, 5g of Na 3 PO 4 , 2.5ml of OP-10, and 250ml of H 2 Soak in O for 10 minutes to remove oil stains on the surface of 304 stainless steel;

[0038] Step 3. Pickling, put the degreased 316 stainless steel into H at room temperature 3 PO 4 75ml, H 2 SO 4 50ml, H 2 Soak 6min in the solution that 0100ml is prepared to remove scale and rust on the stainless steel surface;

[0039] Step 4. Electrolytic polishing, put H 3 PO 4 600ml / L, H 2 SO 4 275ml / L, H 2 0125ml / L, Polyethylene Glycol 8g / L, the solution that glucose 10g / L is formulated as electrolyte, adopt the voltage of 7V, at the temperature of 50 degrees centigrade, the describ...

technical field

[0001] The invention belongs to a stainless steel surface treatment process, in particular to a stainless steel passivation process for improving the corrosion resistance of stainless steel through chemical method for stainless steel surface passivation treatment. technical background

[0002] The most important feature of stainless steel is corrosion resistance. In addition to the material itself, the performance of stainless steel is also related to the quality of passivation on the surface of stainless steel. If the passivation film is incomplete or defective, stainless steel will still be corroded. The passivation film of stainless steel is easily destroyed in many special cases, which will reduce the overall or local corrosion resistance of stainless steel, such as pollutants brought in during welding, forming, weld inspection, etc. The method of pickling and passivation is commonly used in engineering to maximize the corrosion resistance of stainless st...

Examples

Embodiment 1

[0023] A stainless steel passivation process is used to passivate 304 stainless steel, the steps are as follows:

[0024] Step 1. Mechanical polishing, polishing with 400, 600, and 800-grit sandpaper in turn.

[0025] Step 2. Degreasing, at room temperature, put the mechanically polished 304 stainless steel into 5g of Na 2 CO 3 , 3.75g of NaOH, 5g of Na 3 PO 4 , 2.5ml of OP-10, and 250ml of H 2 Soak in O for 10 minutes to remove oil stains on the surface of 304 stainless steel;

[0026] Step 3. Pickling, put the degreased 304 stainless steel into 75ml of H at normal temperature 3 PO 4 , 50ml of H 2 SO 4 , 100ml of H 2 Soak in the solution prepared by O for 6 minutes to remove the scale and rust on the surface of the stainless steel;

[0027] Step 4. electrolytic polishing, the H containing 600ml / L 3 PO 4 , 275ml / L H 2 SO 4 , 125ml / L H 2 The solution that the polyethylene glycol of 0, 8g / L, the glucose of 10g / L is formulated as electrolytic solution, adopts the v...

Embodiment 2

[0035] Adopt a stainless steel passivation process to passivate 316 stainless steel, the steps are as follows:

[0036] Step 1. Mechanical polishing, polishing with 400, 600, and 800-grit sandpaper in turn.

[0037] Step 2. Degreasing, at room temperature, put the mechanically polished 304 stainless steel into 5g of Na 2 CO 3 , 3.75g of NaOH, 5g of Na 3 PO 4 , 2.5ml of OP-10, and 250ml of H 2 Soak in O for 10 minutes to remove oil stains on the surface of 304 stainless steel;

[0038] Step 3. Pickling, put the degreased 316 stainless steel into H at room temperature 3 PO 4 75ml, H 2 SO 4 50ml, H 2 Soak 6min in the solution that 0100ml is prepared to remove scale and rust on the stainless steel surface;

[0039] Step 4. Electrolytic polishing, put H 3 PO 4 600ml / L, H 2 SO 4 275ml / L, H 2 0125ml / L, Polyethylene Glycol 8g / L, the solution that glucose 10g / L is formulated as electrolyte, adopt the voltage of 7V, at the temperature of 50 degrees centigrade, the describ...

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