QPQ Salt Bath Nitriding QPQ composite processing technology
After 10 years of experimental research, CAEC successful developed
the second generation of QPQ technology - deep QPQ technology. The
thickness of compound layer was increased from the original 15 ~ 20
microns to more than 30 ~ 40 microns. Picture 1 shows
Metallographic photos for Deep QPQ treatment and general QPQ
technology treatment
It has been proved by abrasion resistance test, corrosion test,
mechanical property test and permeability layer microstructure test
that component compound layer thickness is multiplied and work
piece’s various performances are greatly improved after second
generation QPQ treatment.
Wear resistance: sliding wear after deep QPQ treatment on 45 steel
demonstrate that wear resistance is four times that of ordinary QPQ
treatment. Work-piece rolling wear experiment shows similar
results.
Corrosion resistance: after deep QPQ treatment of 45 steel
corrosion resistance of weightlessness experiment is 12 times
increase compared to traditional QPQ treatment.
Corrosion resistance is more than 1 times higher. If combined with
sealant, the corrosion resistance of salt spray test can reach more
than 300 h or even higher.
Impact toughness: impact toughness after deep QPQ treatment on 45
steel is 1.98 times higher than ordinary QPQ treatment.
Table 1
Performance Comparison between Deep QPQ treatment and general QPQ
technology treatment
| Treatment Method | Sliding Wear Test
| Weight-Loss Test | Impact Toughness Test
|
| Wear /g | Wear resistance Ratio
| weight lose /g | Corrosion Resistance Ratio | Impact Energy /h | Toughness Ratio
|
| QPQ processing | 0.538 | 1 | 20.99 | 1 | 12.2 | 1 |
| Deep QPQ processing | 0.133 | 4.05 | 1.67 | 12.7 | 24.2 | 1.98 |
QPQ Equipment Series Table
| Equipment model | Crucible Inside Size
| Furnace Dimensions
| Furnace Power
| Remark |
| 300 type | Φ300×500 | Φ900×900 | 15KW | With control cabinet, thermocouple and compensating conductor
|
| 500 type | Φ500×700 | Φ1200×1100 | 25KW |
| 800 type | Φ800×950 | Φ1400×1400 | 50KW |
| 1000 type | Φ1000×1200 | Φ1700×1600 | 75KW |
| Deep type | Φ650×2500 | Φ1350×3200 | 72KW |
| Extra deep type | Φ700×3250 | Φ1400×3900 | 120KW |
Remarks: Customized request is available
QPQ salt bath composite processing special salt series table
| category | QPQ Special Salt | Options Available | Technical characteristics | Remarks |
| ordinary | Basic Salt | Powder and block | suitable for most ferrous metal materials, significant effect will
be achieved especially for medium carbon steel, medium carbon alloy steel and
other materials, and treatment cost is relatively low | Block refers to salt block that is caused by oxidation in salt moisture
and the initial melting of the salt |
| Adjusting Salt | powder
|
Oxide Salt
| powder |
Second generation | Second Generation Basic Salt | Powder and block | Applicable to majority of ferrous materials, especially for high alloy steel, stainless steel and
other materials. Effect will be enhanced significantly. Depth of nitride layer, layer hardness and resistance to corrosion will be improved
compared to ordinary treatment.
|
| second generation adjusting salt | Powder and block |
| powder
|
| High-temp Salt | chunks | Usage temperature 540℃—570℃ | |
| Low-temp Salt | chunks | Usage temperature 525℃—535℃ | |
