CN101871088A - Salt bath formula for treating stainless air conditioning compressor blade by salt bath nitriding treatment and treatment method - Google Patents

Abstract

The invention relates to a salt bath formula for treating a stainless air conditioning compressor blade by salt bath nitriding treatment and a treatment method. The salt bath formula comprises the following compositions in percentage by weight: 5-20 percent of potassium cyanate, 15-25 percent of sodium cyanate, 3-10 percent of lithium carbonate, 8-25 percent of sodium carbonate, 10-30 percent of potassium carbonate, 1-3 percent of sodium hydroxide, 1-5 percent of potassium hydroxide and 1-15 percent of sodium chloride or sodium fluoride. The invention has the advantages that because Li ions and Cl ions are added in the formula, a melting point of salt bath is lowered, and nitridation can be carried out under lower temperature; the activity is favorable, and good appearance and good diffusion layer thickness can be achieved without introducing ammonia; and air cooling can be adopted after salt bath nitridation without adopting the traditional oil cooling mode.

Description

To salt bath formula in the stainless air conditioning compressor blade by salt bath nitriding treatment and treatment process

Technical field

The present invention relates to a kind of stainless air conditioning compressor blade by salt bath nitriding treatment, relate in particular to salt bath formula and the treatment process used in this processing.

Background technology

For improving its wear resisting property and decrease of noise functions, require bright layer thickness 0.005mm in the stainless air conditioning compressor blade (material is 11Crl7), reticulattion is greater than 1 grade, and total infiltration layer is greater than 0.050mm.Usually adopt surface carburization technology, comprise gas nitriding and salt-bath nitriding, the former seldom adopts owing to inefficiency (it is thin excessively that the general treatment time reaches 70 hours bright layers in the nitride layer).

Though conventional salt-bath nitriding gas nitriding relatively makes moderate progress, but because stainless steel surface exists passive film to add the equiatomic existence of alloying elements cr, infiltration to nitrogen has inhibition, so need to adopt highly active salt bath formula just can reach required technical requirements.

Salt-bath nitriding technology of the prior art is with CO ₃And CNO ^-Deng composition by certain proportioning, after melting at 570 ℃--580 ℃ workpiece inserted and handles for some time in the fused salt, make the CNO in the salt ^-Decompose the back nitrogen-atoms and infiltrate the sosoloid that forms FeN compound and certain nitrogen atom concentration in the matrix.In order to improve the salt bath activity, there is patent report to adopt the CNO of higher concentration ^-Also attempt to add K outward, ₂S and feeding ammonia.But this method not only makes operation become complicated, and can produce certain pollution (ammonia escapes into air) to environment.From actual effect, the stainless steel infiltration rate is not significantly improved yet.

Summary of the invention

The technical issues that need to address of the present invention have provided a kind of to the salt bath formula in the stainless air conditioning compressor blade by salt bath nitriding treatment, are intended to solve the above problems.

In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions:

The present invention is made up of and components by weight percentage following compositions: potassium cyanate (KCNO) 5%-20%, Zassol (NaCNO) 15%-25%, Quilonum Retard (Li ₂CO ₃) 3%-10%, yellow soda ash (Na ₂CO ₃) 8%-25%, salt of wormwood (K ₂CO ₃) 10%-30%, sodium hydroxide (NaOH) 1%-3%, potassium hydroxide (KOH) 1%-5%, sodium-chlor (NaCl) or Sodium Fluoride (NaF) l%-15%;

The present invention also provides a kind of salt Bath Nitriding Treatment method, realizes by following steps:

Degreasing: remove the oil film on slide plate surface with the organic solvent of alcohol or dimethylbenzene, through the no greasy dirt of rear surface cleaning that volatilizees naturally;

Preheating: adopt pit furnace, slide plate thermally equivalent when bell is installed blower fan and made preheating, the temperature difference is controlled at ± and 10 ℃; Temperature is between 250 ℃-350 ℃; Time is between 20-30 minute;

Nitrogenize: adopt salt bath formula, the nitriding treatment temperature is between 540 ℃-570 ℃, and the treatment time is 150-300 minute; Described salt bath formula is made up of and components by weight percentage following compositions: potassium cyanate (KCNO) 5%-20%, Zassol (NaCNO) 15%-25%, Quilonum Retard (Li ₂CO ₃) 3%-10%, yellow soda ash (Na ₂CO ₃) 8%-25%, salt of wormwood (K ₂CO ₃) 10%-30%, sodium hydroxide (NaOH) 1%-3%, potassium hydroxide (KOH) 1%-5%, sodium-chlor (NaCl) or Sodium Fluoride (NaF) 1%-15%;

Cooling: adopt air cooling, below the back air cooling to 100 ℃ of coming out of the stove; Or adopt direct oil cooling;

Polishing.

Compared with prior art, the invention has the beneficial effects as follows: owing in prescription, add Li and Cl ion, the fusing point in the salt bath is reduced, can carry out nitrogenize at a lower temperature; Active good, ammonia needn't be fed and good surface appearance and alloying layer thickness can be reached; Behind salt-bath nitriding, air cooling can be adopted, and traditional oil cooling mode needn't be adopted.

Embodiment

Below in conjunction with embodiment the present invention is described in further detail:

The present invention is made up of and components by weight percentage following compositions: potassium cyanate (KCNO) 5%-20%, Zassol (NaCNO) 15%-25%, Quilonum Retard (Li ₂CO ₃) 3%-10%, yellow soda ash (Na ₂CO ₃) 8%-25%, salt of wormwood (K ₂CO ₃) 10%-30%, sodium hydroxide (NaOH) 1%-3%, potassium hydroxide (KOH) 1%-5%, sodium-chlor (NaCl) or Sodium Fluoride (NaF) 1%-15%.

Embodiment 1

Potassium cyanate (KCNO) 18%, Zassol (NaCNO) 22%, Quilonum Retard (Li ₂CO ₃) 5%, yellow soda ash (Na ₂CO ₃) 20%, salt of wormwood (K ₂CO ₃) 21%, sodium hydroxide (NaOH) 1%, potassium hydroxide (KOH) 3%, sodium-chlor (NaCl) 10%.

Embodiment 2

Potassium cyanate (KCNO) 18%, Zassol (NaCNO) 22%, Quilonum Retard (Li ₂CO ₃) 5%, yellow soda ash (Na ₂CO ₃) 20%, salt of wormwood (K ₂CO ₃) 28%, sodium hydroxide (NaOH) 1%, potassium hydroxide (KOH) 3%, sodium-chlor (NaCl) 3%.

Mainly be to constitute in the component of the salt-bath nitriding among the present invention by cyanate radical and carbonate, its reaction mechanism is that cyanate and oxygen reaction generate nitrogen and carbonate, wherein nitrogen-atoms infiltrates in the matrix, along with the carrying out used up cyanate radical and can be mended by adding regenerant salt of reaction, this prescription salt can recycle.

CNO ^-+O ₂→[C]+[N]+CO ₃ ^2-

CO ₃ ^2-+ Z (regenerant salt) → CNO ^-

Preparation method of the present invention is as follows:

Urea and carbonate and other component thorough mixing are put into crucible after evenly, and insulation can be produced in batches in 2 hours after 600 ℃ of high temperature melt; Use the same method and to obtain regenerant salt.

The mechanism of action of the present invention is: owing to added the active anion that contains F or Cl in the salt bath, this ion at high temperature can make the passive film of stainless steel surface dissociate, and activates its workpiece surface, and it is more easy to make that the infiltration of nitrogen becomes, even at low CNO ^-Still can obtain infiltration rate faster under concentration and the low treatment temp, and need not to feed ammonia.And the activity of Li ion itself is higher than Na and K ion, so add the activity that an amount of Li can improve salt bath.

Claims (4)

1. one kind to the salt bath formula in the stainless air conditioning compressor blade by salt bath nitriding treatment, form and components by weight percentage by following compositions: potassium cyanate 5%-20%, Zassol 15%-25%, Quilonum Retard 3%-10%, yellow soda ash 8%-25%, salt of wormwood 10%-30%, sodium hydroxide 1%-3%, potassium hydroxide 1%-5%, sodium-chlor or Sodium Fluoride 1%-15%.

2. salt bath formula according to claim 1, wherein: potassium cyanate 18%, Zassol 22%, Quilonum Retard 5%, yellow soda ash 20%, salt of wormwood 21%, sodium hydroxide 1%, potassium hydroxide 3%, sodium-chlor 10%.

3. salt bath formula according to claim 1, wherein: potassium cyanate 18%, Zassol 22%, Quilonum Retard (Li ₂CO ₃) 5%, yellow soda ash 20%, salt of wormwood 28%, sodium hydroxide 1%, potassium hydroxide 3%, sodium-chlor 3%.

4. method to the stainless air conditioning compressor blade by salt bath nitriding treatment, realize by following steps:

Degreasing: remove the oil film on slide plate surface with the organic solvent of alcohol or dimethylbenzene, through the no greasy dirt of rear surface cleaning that volatilizees naturally;

Preheating: adopt pit furnace, slide plate thermally equivalent when bell is installed blower fan and made preheating, the temperature difference is controlled at ± and 10 ℃; Temperature is between 250 ℃-350 ℃; Time is between 20-30 minute;

Nitrogenize: adopt salt bath formula, the nitriding treatment temperature is between 540 ℃-570 ℃, and the treatment time is 150-300 minute; Described salt bath formula is made up of and components by weight percentage following compositions: potassium cyanate 5%-20%, Zassol 15%-25%, Quilonum Retard 3%-10%, yellow soda ash 8%-25%, salt of wormwood 10%-30%, sodium hydroxide 1%-3%, potassium hydroxide 1%-5%, sodium-chlor or Sodium Fluoride 1%-15%;

Cooling: adopt air cooling, below the back air cooling to 100 ℃ of coming out of the stove; Or adopt direct oil cooling;

Polishing.