New Wear-Resistant and Corrosion-Resistant Materials

Introduction to New Wear-Resistant and Corrosion-Resistant Materials

Through theoretical demonstration and practical experience, it is known that the erosion mechanisms of pumps during operation mainly include three types:

1. The pump's flow surfaces suffer mechanical wear due to high-speed impacts from various forms of solid particles with certain particle sizes and hardness in the working medium.

2. High-pressure vapor bubbles formed by residual air in the pumped medium collapse, causing impact damage to the flow component surfaces, resulting in cavitation.

3. Electrochemical reactions occur between the medium and flow components, causing electrochemical corrosion.

To make the material resistant to mechanical wear while also having good resistance to cavitation and electrochemical corrosion, based on analysis data of various wear-resistant materials at home and abroad and erosion test data, by comparing their metallographic microstructure and chemical composition, several related materials must be selected for formulation. Special smelting and heat treatment are used so that the new material adapts to the three major erosion characteristics, while also possessing good toughness and machinability. After numerous smelting tests, repeated discussions, process improvements, multiple samplings, chemical analyses, inspections, and analyses, a material meeting the above requirements was finally developed.

During smelting, steelmaking pig iron and ferrochrome are selected as the main raw materials, controlling C and Si content, adding W, Mo, Ni, V, Ti, Cu, Al, and other materials as ingredients and inoculants, and using rare earth alloys for spheroidizing treatment. High C and Si content (greater than 3.2%) results in eutectic and hypereutectic structures, precipitating coarse eutectic carbides and primary carbides, which reduce material toughness and easily cause cracks; low C and Si content leads to a network trend of eutectic carbides, reducing hardness. After high-temperature heat treatment, the amount of retained austenite in the matrix increases, the electrode potential gradient of the microstructure phases increases, and electrochemical corrosion resistance is poor. Finding reasonable C and Si content is key to overcoming respective defects and improving wear and corrosion resistance.

Cr: is the main element of this material, with content controlled between 16-33%.

W: can change the morphology and distribution of eutectic carbides, forming high-hardness WC with HV=2500-3000, improving hardenability, which benefits wear and corrosion resistance.

Mo: significantly improves hardenability, together with W compensates for the insufficient hardenability of pure chromium cast iron, refines and homogenizes the structure, suppresses pearlite formation, leading to widespread martensite formation.

V: strongly and stably promotes eutectic carbide formation, forming high-hardness VC particles (HV:2800) distributed in the structure, acting as foreign nuclei during crystallization, significantly inhibiting grain growth during crystallization.

Cu, Ti, Al, etc. improve the material's microstructure.

Rare earth: used for composite inoculation treatment, removing harmful impurities from molten iron.

Through research, selection, and manufacturing processes, a new type of material was developed.

The microstructure of this new wear-resistant and corrosion-resistant material consists of a single tough martensite matrix uniformly embedded with a certain amount of isolated alloy carbides with very high hardness, HRC greater than 65. Performance tests conducted by research institutions in Tianjin, Wuhan, and others show its comprehensive performance surpasses many domestic and foreign wear-resistant alloy materials.

Technical Advantages

Advancement

Widely adopting advanced design theories

Optimized design of flow components (impeller, casing, front and rear wear plates, auxiliary blades).

Comprehensive use of advanced R&D software

CAD drafting and 3D modeling;

Computer-aided process planning (CAPP) simulation;

Computational fluid dynamics (CFD) analysis, shortening R&D cycles and improving R&D quality;

Rationality

Reasonable model spectrum design, convenient for user selection

Tianze Pump Company's model spectrum design has minimal overlap areas and basically no blank zones, facilitating user selection.

Reasonable structure, excellent pump body performance

(1) Uses a horizontal split light oil lubricated bracket, which is easier to maintain and adjust and more durable compared to grease-lubricated brackets;

(2) Shaft: large diameter, good rigidity, short cantilever, will not bend or vibrate;

(3) Cooling system:

Generally used when the temperature of the conveyed liquid is >70°C or bearing temperature is >80°C.

A. Internal cooling: oil cooling, placed on the bracket body;

B. External cooling: placed on the bracket cover.

C. Function: improves the shaft working environment, allowing the shaft to operate under lower temperature conditions, greatly extending the service life of the shaft and bearings.

Sealing

(1) Auxiliary impeller + packing seal

Advantages: low cost, low maintenance, simple repair, long service life, significantly increased mean time between failures (MTBF) of the whole machine;

(MTBF) greatly improved;

Disadvantages: leakage can be minimized but cannot be completely eliminated.

(2) Mechanical seal

Advantages: completely leak-free, suitable for multi-stage series use;

Disadvantages: high cost, large maintenance workload, relatively shorter service life.

Pump Head

(1) Pump casing: double casing structure;

(2) Flow channel: wide and smooth, good anti-clogging performance, good cavitation resistance;

(3) Outlet: adjustable in 8 different directions, adaptable to different working environments;

(4) Auxiliary blades: auxiliary blades are set before and after the impeller to reduce leakage and extend impeller service life;

(5) Flow-through components: impeller, casing, front wear plate, rear wear plate, auxiliary impeller; all made of high-chromium wear-resistant alloy Cr28, with a service life 10% longer than similar domestic products (Cr26 or Cr27).

Strict process control enhances product reliability

Entire production process

Smelting and casting process

Machining and assembly process

Wear-resistant, corrosion-resistant, and durable

Flow-through components mainly include: impeller, casing, front wear plate, rear wear plate, auxiliary impeller, pressure relief cover.

Our company independently develops and continuously improves all flow-through components:

A Material is high-chromium wear-resistant alloy Cr28

B Material hardness HRC>65

C Wear resistance, corrosion resistance, and durability are 10% higher than similar domestic products

Attentive service

Huanaipump Service Commitment:

Strictly deliver on time as required by the owner; if delayed, compensation will be made to the owner according to a mutually agreed proportion.
Send personnel on time as required by the owner to provide free installation and debugging guidance, and provide free training for the owner's operation and maintenance technicians.
Our company promises to dispatch personnel for mechanical parts service within 24 hours upon receiving notification.
Responsible for free technical training for the owner's relevant personnel before and during equipment installation and debugging; provide lifetime warranty for supplied products and timely, attentive service to users.
Provide the owner with a complete set of technical documentation and promptly answer technical questions encountered by the owner.