IV. Features Description

A. Corrosion Resistance

1. Passive Film Formation

   Both stainless steel 304 and 316 in TIANYU’s valve form a passive film on their surfaces when exposed to oxygen. This film acts as a barrier, preventing further oxidation and corrosion. In the case of stainless steel 316, the presence of molybdenum improves the stability and integrity of this passive film, making it more resistant to pitting and crevice corrosion, especially in harsh environments.

2. Applicability in Corrosive Environments

   TIANYU’s valve can be used in a wide range of corrosive media. For example, in the chemical industry, when handling acids like acetic acid (for stainless steel 304 in dilute concentrations) or in more aggressive environments with sulfuric acid (where stainless steel 316 may be more appropriate), the valve can maintain its structural integrity and functionality over time.

B. High – Strength Construction

1. Mechanical Properties of Stainless Steel

   Stainless steel, especially in the 304 and 316 grades, has high tensile strength. This means that the valve can withstand significant internal pressure without deforming or failing. The high – strength nature of the material also allows it to endure external mechanical stresses, such as those from pipeline vibrations or thermal expansion and contraction. In industrial settings where pipelines may be subject to various forces, the TIANYU valve’s high – strength construction ensures its long – term reliability.

C. Tight Sealing

1. Sealing Mechanisms

   TIANYU’s valve is designed with precision – engineered sealing components. Depending on the type of valve (e.g., ball valve, gate valve, etc.), the sealing surfaces are carefully machined to ensure a tight fit. For example, in a ball valve, the ball and the seat are designed to create a seal that prevents leakage. The use of high – quality sealing materials, often compatible with the stainless – steel body, further enhances the sealing performance. This tight – sealing feature is crucial in applications where fluid containment is essential, such as in the transportation of hazardous chemicals or in high – purity fluid systems.

V. Manufacturing Process

A. Raw Material Selection

1. Quality Assurance of Stainless Steel

   TIANYU sources high – quality stainless – steel raw materials from reputable suppliers. The stainless – steel alloys are carefully inspected to ensure they meet the required chemical composition and mechanical property standards. For stainless steel 304 and 316, the chromium, nickel, and molybdenum (in the case of 316) contents are verified through chemical analysis. The raw materials also undergo physical tests to check for any inclusions or defects that could affect the final valve quality.

B. Forging or Casting (Depending on Valve Type)

1. Forging Process
   • Steps: If the valve is to be forged, the stainless – steel billet is heated to a suitable temperature range. For stainless steel, this is typically around 1050 – 1250°C. Once heated, the billet is placed in a forging press or hammer. The forging process involves shaping the metal by applying compressive forces, which refine the grain structure of the steel. This results in a more homogeneous and stronger material. For example, in the forging of a valve body, the billet is gradually shaped into the desired form, with multiple passes to ensure proper shaping and density.
2. Casting Process
   • Steps: In the case of casting, a mold is created based on the design of the valve. The mold can be made of sand, metal, or other suitable materials. The stainless – steel is melted in a furnace, such as an electric arc furnace or an induction furnace. The molten metal is then poured into the mold. After solidification, the casting is removed from the mold. Casting allows for the production of complex – shaped valve components with relatively less machining required compared to forging. However, careful control of the casting process is necessary to avoid defects such as porosity or shrinkage.

C. Machining

1. Precision Machining Operations

   After forging or casting, the valve components undergo extensive machining. This includes operations such as turning, milling, drilling, and grinding. Turning is used to create cylindrical surfaces, such as the valve stem or the inner bore of the valve body. Milling is employed to create flat surfaces, slots, or to cut gears (if applicable). Drilling is used to create holes for bolts, fluid passageways, or for actuator connections. Grinding is used to achieve high – precision surface finishes, especially on sealing surfaces. The machining processes are carried out using computer – numerical – control (CNC) machines to ensure consistent accuracy and repeatability.

D. Heat Treatment

1. Annealing and Stress Relieving

   For both forging and casting processes, heat treatment is often necessary. Annealing is performed to relieve internal stresses in the stainless – steel components. This is typically done by heating the valve to a specific temperature (around 1050 – 1100°C for stainless steel 304 and 316) and then slowly cooling it. Stress – relieving heat treatment helps to prevent cracking and distortion during subsequent machining and in – service use. It also improves the ductility of the material, making it more resistant to fatigue.

E. Assembly

1. Component Inspection

   Before assembly, all valve components are thoroughly inspected. The machined parts are checked for dimensional accuracy, surface finish, and any signs of defects. Sealing components are inspected for proper shape, flexibility, and material integrity. Actuator components (if the valve is actuated) are also inspected to ensure they are in good working condition.

2. Assembly Procedures

   The valve is assembled in a clean and controlled environment. The components are carefully fitted together according to the design specifications. Sealing elements are installed with precision to ensure a proper seal. Bolts and fasteners are tightened to the recommended torque values to ensure the integrity of the assembly. After assembly, the valve undergoes a final functional test to ensure that it operates smoothly and meets the performance requirements.