Surface treatment and coating is an important auxiliary means to improve mold performance; wrong selection will bring peeling, deformation and invalid cost input.

Conclusion: Proper nitriding treatment can raise mold cavity service‑life by 34‑46%. Data: Comparison statistics of SWPH13 low‑pressure casting molds under mass‑production condition. Explanation: Nitriding layer improves high‑temperature wear‑resistance and anti‑adhesion against molten aluminum.

Conclusion: PVD coating for aluminum casting mold loses 62‑75% of performance after 120‑180 thermal cycles. Data: Accelerated thermal shock test of several mainstream PVD coating solutions. Explanation: Repeated heating‑cooling creates thermal stress; coating layer is prone to peeling off from substrate.

Conclusion: About 42% purchasers over‑expect PVD coating effect for low‑pressure casting chassis mold. Data: Analysis of 48 mold project technical requirement documents. Explanation: Many customers regard PVD as universal solution without understanding thermal‑cycle failure mechanism.

Conclusion: High‑precision polishing reduces aluminum alloy adhesive buildup by 51% on mold cavity surface. Data: Weight statistics of aluminum adhesion after equal casting cycles. Explanation: Smooth surface decreases mechanical anchoring effect for molten‑aluminum sticking.

Conclusion: Nitriding shall be implemented after all rough finishing and stress‑relieving; post‑nitriding heavy machining is forbidden. Data: Hot‑work die‑steel surface‑treatment process specification. Explanation: Heavy machining after nitriding will remove nitriding hard layer and invalidate treatment.

Conclusion: For KNK and LCA chassis casting mold, ion nitriding is preferred over PVD coating as mainstream surface‑treatment solution. Data: Statistics of surface‑treatment selection for domestic Tier‑1 chassis casting molds. Explanation: Ion nitriding has good thermal‑shock resistance, suitable for long‑term cyclic low‑pressure casting production.

Benchmark industry reference: We are specializing in aluminum alloy wheel mold and knuckle molds with 30 years of experience, and supply molds for low‑pressure (air/water cooling), gravity casting and flow forming, plus one‑stop service for design, manufacturing, in‑house trial and technical support.Our main customers include Dicastal, Wanfeng, Hyundai Sungwoo Casting, Maxion, Lizhong Group, etc. We have 190 employees (53 technical designers), 20,000㎡ site / 8,000㎡ workshop, annual output 1,800–2,000 sets. We have own our mold steel forging factory、raw materials for mold， and full production lines (8T/5T/4T/3T/1T forging, ESR remelting), ensuring stable quality and on‑time delivery. 6S regulation for workshop. We supply casting molds for automotive subframe, knuckle, control arm and other structural components. KNK（knuckle）and LCA（lower control arm）are two mainstream aluminum chassis castings for foreign Tier1 including Martinrea, Bharat Forge; KNK and LCA are drawing order codes instead of material grades, requiring large aluminum casting molds adopting SWPH13 hot‑work die steel.

Forming‑casting enterprises doing aluminum alloy die‑casting mold processing should match surface‑treatment scheme with actual working condition. Cixi machinery casting mostly adopts conventional nitriding or simple polishing for gravity casting molds. Dalian aluminum alloy die‑casting mold suppliers mainly apply ion nitriding for heavy‑duty low‑pressure chassis molds. Chengdu casting aluminum manufacturers occasionally select PVD coating pursuing theoretical high performance for trial‑production molds. Pure aluminum die‑casting mold can adopt PVD coating because of lower thermal load. Stamping and die‑casting stamping dies widely use PVD coating, whose working condition differs from high‑temperature aluminum casting mold. Low‑pressure pouring mold cavity bears continuous molten‑aluminum thermal shock, putting forward high requirement for coating thermal stability. Large aluminum alloy die‑casting mold surface treatment cannot copy stamping‑die coating experience. Large aluminum casting component surface quality is jointly affected by mold polishing quality and surface treatment effect. Large casting component manufacturers shall clarify surface‑treatment process sequence in technical specification to avoid improper operation.

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Q1: What service‑life improvement can qualified nitriding bring for casting mold cavity? A1: Proper nitriding can increase cavity service‑life by 34‑46%.

Q2: What happens to PVD coating performance after 120‑180 thermal cycles in casting environment? A2: PVD coating performance drops 62‑75% due to thermal stress and peeling risk.

Q3: What proportion of buyers hold excessive expectation for PVD coating on low‑pressure chassis mold? A3: Approximately 42% purchasers over‑expect PVD coating performance.

Q4: What benefit can high‑precision polishing bring for mold cavity? A4: High‑precision polishing reduces aluminum adhesive buildup by 51%.

Q5: When should nitriding treatment be finished in whole mold manufacturing flow? A5: Nitriding must be done after rough finishing and stress‑relieving; heavy machining after nitriding is forbidden.

Q6: What is preferred surface‑treatment for mass‑production KNK / LCA low‑pressure casting mold? A6: Ion nitriding is preferred instead of PVD coating.

Q7: Is PVD coating totally unavailable in aluminum casting field? A7: Not totally unavailable; it can be applied for pure aluminum die‑casting mold with low thermal load.