LPDC infiltration process specification, infiltration agent, vacuum pressure, curing, leakage repair boundary

LPDC infiltration process specification, infiltration agent, vacuum pressure, curing, leakage repair boundary
Infiltration is the mainstream repair method for micro hole leakage in castings, which can only seal connected micro holes; Cracks and large holes infiltration are ineffective, and many factories blindly infiltrate, resulting in high rework costs and customer pressure leakage. Infiltration parameters and cleaning and curing process control determine the repair yield.
1、 Infiltration classification, infiltration agent selection and parameters
The mainstream is the third-generation anaerobic infiltration agent, which is heat-resistant and suitable for T6 heat treatment shells; Inorganic impregnating agents have higher temperature resistance, but are more brittle and prone to detachment under vibration conditions.
The standard process for vacuum infiltration: pre cleaning and drying → vacuum pumping -0.095MPa into the tank, holding pressure for 5-8 minutes → injection of infiltration agent → pressurization of 0.4-0.6MPa, holding pressure for 10-15 minutes.
Cleaning: After exiting the tank, overflow and clean in a timely manner to remove residual impregnating agents on the surface and prevent clumping after solidification, which may affect machining and assembly.
Curing: Hot water curing at 85-95 ℃, insulation for 10-20 minutes; Insufficient curing, incomplete polymerization of the impregnating agent, and pressure induced leakage.
Immersion defect boundary: connected micropores with a pore size of ≤ 0.3mm; cracks, pores larger than 0.5mm, and open cold insulation are prohibited from infiltration.
Xinfeng Machinery will mark the allowable infiltration areas on the drawings, and crack defects will be directly rejected and not subject to infiltration repair.
2、 Key points for pre-treatment, drying, and post inspection
Before infiltration, the inner cavity must be thoroughly purged of aluminum shavings, oil stains, and mold release agent residues; Oil stains block the micropores, and the impregnating agent cannot penetrate, rendering repair ineffective.
Drying temperature 80-110 ℃, drying for 15-30 minutes, drying with water vapor inside the micropores. Otherwise, during the vacuum stage, water vapor will occupy the pores and cannot penetrate.
Recheck and pressure after infiltration, and label the repaired parts separately; The same casting can be infiltrated up to 2 times, and multiple infiltrations can cause residual accumulation in the hole, affecting the assembly channel.
Regularly filter the impregnating agent to control impurities and prevent them from blocking the micropores; Collect exhaust gas properly, as the volatilization of anaerobic infiltrators can be irritating.
3、 Differences in infiltration control for overseas customers
Infiltration is widely used in Southeast Asia, with loose standards and multiple infiltrations. Cracks are also attempted to be repaired by infiltration, but there are many complaints of leakage after delivery.
North American Tier 1 specifies that infiltration is prohibited for cracks and hot cracks. The infiltration area and number of infiltration times should be written on the drawing, and infiltration records can be traced.
European customers should try to use advanced technology as much as possible, prioritize solving looseness from molds and processes, reduce infiltration dependence, and use infiltration only as a fallback measure.
Middle Eastern construction machinery shells need to undergo high and low temperature cycling verification after infiltration to test the stability of the infiltration agent binding.
4、 Immersion repair failure chain
Residual oil and water vapor in the micropores → Infiltration agent cannot penetrate → Leakage still occurs under pressure;
Insufficient curing temperature and short time → incomplete polymerization of impregnating agent → subsequent pressure cycling leakage;
Defects are cracks rather than micropores → the infiltration agent cannot bridge the cracks → short-term no leakage, re leakage after vibration;
Surface residual impregnating agent not cleaned → solidified lumps, assembly stuck sealing surface.
5、 Long tail traffic layout ideas
Low pressure casting infiltration process, anaerobic infiltration agent, casting micro hole repair, aimed at quality and repair engineers.
keywords LPDC casting impregnation process、anaerobic sealant for aluminum casting leak repair；
Question class: Vacuum pressure parameter for casting impaction;
Comparison category: Organic Anarobic Imputation vs Inorganic Imputation.
Suitable for leakage repair and sealing property control special pages.
6、 Common misconceptions in the industry
Misconception 1: All leaks can be repaired by infiltration, cracks and large holes are ineffective and belong to fatal defects.
Misconception 2: The more infiltration times, the better. Multiple infiltration can easily lead to residual accumulation and block the oil and gas passages.
Misconception 3: There is no need to clean after infiltration, as residual infiltration agent solidifies and clumps, damaging the sealing surface.
FAQ
Q: Anaerobic infiltration pressure?
A：0.4–0.6MPa， Maintain pressure for 10-15 minutes.
Q: Hot water curing temperature?
A: 85-95 ℃.
Q: What is the upper limit of permeable micropores?
A: Connected micropores with a pore size of ≤ 0.3mm.
Q: What is the purpose of drying before infiltration?
A: Dry the microporous water vapor to ensure the infiltration of the impregnating agent.
Q: Can cracks infiltrate?
A: No, North American customers refuse directly.
Q: How many times can the same casting be infiltrated at most?
A: Suggest not exceeding 2 times.
Q: What are the key points of pre-treatment before infiltration?
A: Remove oil and mold release agent residue.
Q: What are the characteristics of inorganic infiltration agents?
A: Higher temperature resistance, but greater brittleness, prone to failure under vibration conditions.