In industrial pipeline systems, even a small leak can cause serious safety accidents or environmental pollution. Valves and pipe fittings are key control and connection components. Their quality directly determines the reliability and lifespan of the entire system.
QD specializes in using investment casting to produce industrial valves and pipe fittings. Our castings have a dense structure, precise dimensions, and excellent sealing performance. They help ensure the safe and stable operation of your systems.
Why Choose Investment Casting?
Investment casting works best for small to medium castings. These parts have complex shapes, tight size limits, and smooth surfaces. It is especially suitable for valves and pipe fittings with inner channels, threads, or curved surfaces.
Key advantages:
- High dimensional accuracy: It reaches CT4 to CT6 tolerance grades. This ensures precise assembly.
- Excellent surface finish: Surface roughness can reach Ra 3.2–6.3 μm. This reduces the need for extra machining.
- Wide material compatibility: It works with carbon steel, stainless steel, and various alloy steels.
- Strong structural integrity: The part is cast as one solid piece. No welded joints. This avoids potential defects.
Quality Focus 1: Density
Castings must be dense to prevent leaks. If there are defects like shrinkage or air pockets inside, leakage can happen even under low pressure. QD ensures high density for valves and pipe fittings in these ways:
1. Optimized Gating System Design
We use computer simulations to model solidification. This helps us predict areas with shrinkage risks early.
We design proper gating and riser systems. This ensures the casting gets continuous and sufficient liquid metal feeding as it solidifies.
2. Key Process Controls
- Directional solidification control: We control cooling to ensure solidification progresses from the farthest point toward the riser.
- Mold preheating control: We precisely control mold preheating temperature. This prevents uneven shrinkage caused by large temperature differences.
- Matching alloy composition and pouring temperature: We adjust process parameters based on material properties. This ensures good fluidity while reducing shrinkage.
QD’s Advantage: We have years of investment casting data and simulation experience. We identify and solve density issues during the design stage.
Quality Focus 2: Dimensional Stability
If valve and pipe fitting connections have large size errors, they will not seal well, be hard to assemble, or cause system failure. QD ensures dimensional stability through these methods:
1. Mold Precision Control
We use CNC machining or 3D printing to produce wax pattern molds. This ensures cavity dimension accuracy.
We check mold wear regularly and set maintenance schedules. This guarantees consistent wax patterns.
2. Shell-Building Process Management
Wax patterns can warp during shell building. We control this by:
- Multi-layer composite shells: We use a silica sol-ethyl silicate process. This makes the shell stronger and more stable.
- Strict room conditions: The shell-building workshop has constant temperature and humidity. This reduces size changes from the environment.
- Automated shell-building lines: This reduces human error and improves repeatability.
3. Post-Processing and Inspection
- Dedicated fixtures for machining: This ensures a consistent reference for key areas like flange faces and threaded valve connections.
- CMM inspection: We perform batch sampling checks to confirm all dimensions meet drawing requirements.
QD’s Advantage: We have a full dimensional control system covering mold design, shell building, and post-processing. This makes every product easy to install and reliably sealed.
Commonly Used Materials for Valve and Pipe Fitting Castings
We often provide castings made from the following typical materials:
| Material Number | Key Features | Common Uses |
| WCB (A216-WCB) | Good welding and machining. Medium strength. | Water, oil, gas systems. Low-temperature, non-corrosive media. |
| 304 Stainless Steel | Excellent corrosion resistance and formability. | Food, chemical, pharmaceutical industries. Weak corrosive environments. |
| 316 Stainless Steel | Contains Molybdenum. Better resistance to pitting and crevice corrosion. | Seawater, chloride environments. Chemical processing. |
| Duplex Steel 2205 | High strength. Resists stress corrosion and pitting well. | Offshore platforms, petrochemical, desulfurization systems. Harsh conditions. |
Note: Material selection should consider the medium, temperature, pressure, and cost together. We offer material selection advisory services.
Additional Processing Support
In addition to cast blanks, QD also offers the following machining services:
Rough Machining: Removing gates, risers, and flash.
Semi-Finishing: Pre-machining sealing surfaces and threaded connections, leaving allowance for final precision machining.
Non-Destructive Testing: Providing Penetrant Testing (PT) and Radiographic Testing (RT) to ensure internal quality.
QD’s Advantage: We provide one-stop casting solutions. This reduces handling steps, shortens lead times, and helps control your overall cost.
Contact Us
A reliable casting supplier is the foundation of system safety for valves and pipe fittings.
QD has mature investment casting processes, strict quality control, and extensive industry experience. We welcome you to partner with us for your valve casting projects.
FAQ
1. What is the largest valve size you can produce with investment casting?
It is typically used for valves from DN15 to DN300. The exact size depends on the design and material. We can review your drawings and confirm.
2. Do you accept small-batch orders?
Yes. We have flexible production capabilities. We support small-batch, multi-variety orders. This is especially suitable for customized, high-value valves and pipe fittings.
3. What is the general lead time for castings?
About 20–30 days for standard materials and designs. It may take longer for complex or special materials. We provide progress tracking services.
4. Can you provide material certificates?
Yes. We provide material reports with each batch. We can also provide third-party inspection reports.
5. How do you handle surface defects on castings?
We use TIG repair welding and grinding. The repaired areas are checked by non-destructive testing to confirm the valve casting is defect-free.
6. Do you allow factory inspections by customers?
Yes. We welcome customers or third parties to conduct on-site inspections during key processes like shell building, pouring, and final testing.