Opportunities and Challenges for Brass Bars and Ingots in the Sanitary Ware Industry

On April 22, at the CCIE 2025 SMM (20th) Copper Industry Conference & Copper Industry Expo – Copper Pipe and Billet Processing Industry Development Forum, hosted by SMM Information & Technology Co., Ltd., SMM Metal Trading Center, and Shandong Aisi Information Technology Co., Ltd., with Jiangxi Copper Corporation and Yingtan Land Port Holdings Co., Ltd. as the main sponsors, Shandong Humon Smelting Co., Ltd. as the special co-organizer, and Xinhuang Group and Zhongtiaoshan Nonferrous Metals Group Co., Ltd. as co-organizers, Lao Xicai, General Manager of Guangdong Weiqiang Copper Technology Co., Ltd., shared insights on the impact of the metallurgical quality of brass ingots and brass bars on the microstructure and properties of sanitary ware products.

01 Impact of Metallurgical Quality on Microstructure

Impact on Microstructure

01 Grain Size and Shape

Grain size directly affects the strength and toughness of materials, while grain shape significantly impacts the fatigue life of materials. The quantity and distribution of grain boundaries also play a crucial role in material properties.

02 Analysis of Microscopic Defects

Casting defects such as shrinkage cavities, porosity, and inclusions have a noticeable impact on the mechanical, processing, and physical properties of materials. Comprehensive control is required in terms of raw material purity, alloy composition design, melting and refining processes, and casting crystallization.

03 Analysis of Microstructure Homogeneity

A homogeneous microstructure can enhance the overall performance of materials, while inhomogeneity can lead to stress concentration and performance degradation. Homogeneity significantly impacts the corrosion resistance of sanitary ware products.

Grain Size and Shape

► Impact of Grain Size

Coarse grains have a smaller total grain boundary area, resulting in weaker grain bonding, reduced strength and toughness, and decreased corrosion resistance and weldability. In contrast, relatively fine grains offer better mechanical, physical, and processing properties.

► Impact of Grain Shape

Equiaxed grains formed during casting exhibit good isotropy and are suitable for deformation processing. The growth of columnar grains needs to be suppressed by adding inoculants.

Columnar grains: Arranged in specific directions, they offer good axial strength but reduced transverse plasticity and fatigue resistance, and are prone to defects such as shrinkage cavities and cracks.

Grain size and shape directly determine the mechanical properties, processing performance, and environmental resistance of materials by influencing dislocation movement, grain boundary characteristics, and microstructure homogeneity. The control of grain structure can be achieved through the synergistic optimization of composition design (such as microalloying) and process control (such as rapid solidification, cold working rate, and heat treatment regimes), thereby enhancing metallurgical quality.

Phase Composition and Distribution

Microstructural characteristics of the α+β phase: The α+β phase exhibits good comprehensive properties; the α phase, with a face-centered cubic crystal structure, offers excellent plasticity and is suitable for cold working; the β phase, with a body-centered cubic crystal structure, has high hardness but low plasticity and is suitable for hot working.

Microstructural characteristics of the Pb phase: The Pb phase is distributed in the form of fine particles at grain boundaries or phase boundaries, acting as a chip breaker and self-lubricant during machining, reducing tool wear, improving surface finish, and enhancing processing efficiency.

Impact of phase boundary distribution: A uniform phase composition and distribution significantly affect the mechanical, processing, and surface treatment properties of materials. Segregation of the β phase and Pb phase can lead to local stress concentration, significantly reducing strength, corrosion resistance, and fatigue resistance. It can also result in unstable adhesion to coatings, affecting aesthetics and long-term corrosion resistance.

02 Impact of Metallurgical Quality on Physical Properties

Impact of Brass Ingots and Brass Bars on the Properties of Sanitary Ware Products

► Impact on the Microstructure of Brass Products

Microstructure density and homogeneity: During the solidification of high-temperature molten metal, volume shrinkage occurs. If not promptly supplemented, shrinkage cavities (porosity) may form at the last solidification site. Inhomogeneous solidification leads to the presence of coarse columnar and dendritic grains, often accompanied by porosity, gas pockets, and inclusions between grains, affecting the forging and processing performance of the material.

► Impact on the Properties of Sanitary Ware Products

Strength and toughness: High-quality brass provides better mechanical properties. Corrosion resistance: Brass with good metallurgical quality exhibits superior corrosion resistance. Processability: Good brass materials offer high processing efficiency, reducing production costs.

► Impact on the Durability of Sanitary Ware Products

Wear resistance: High-quality brass offers better wear resistance, enhancing product durability. Fatigue resistance: Good brass materials perform better under repeated stress. Weldability: The welding performance of brass affects product durability.

► Changes in Processability

1. Surface treatment performance (electroplating and corrosion resistance)

An excellent copper substrate ensures good polishing performance, freedom from impurities and porosity, and perfect bonding with coatings, resulting in aesthetically pleasing and durable products.

2. Formability (cold/hot working performance)

Microstructure affects formability; a homogeneous microstructure facilitates various processing deformations, while an inhomogeneous microstructure can easily lead to fractures and dimensional inaccuracies.

3. Optimization of welding performance

Welding methods affect welding performance; optimizing welding parameters improves welding performance; appropriate welding materials can enhance welding performance.

03 Impact of Metallurgical Quality on Alloy Trace Elements

► Role of Microalloying

04 Opportunities and Challenges for Brass Bars and Copper Ingots in the Sanitary Ware Industry

► Application Prospects of Brass and New Materials in Sanitary Ware Products

Application of Brass Bars in Sanitary Ware Products: In 2024, brass bars, with their excellent corrosion resistance and good processing and forging properties, have broad application prospects in sanitary ware products. Their unique color and texture after polishing and electroplating make sanitary ware products appear more high-end and elegant, and they also exhibit excellent performance in terms of environmental protection and durability.

Potential of Copper Ingots in the Sanitary Ware Industry: Copper ingots, due to their excellent casting properties and durable stability after polishing and electroplating, are widely used in the manufacture of high-end sanitary ware bodies. With the improvement of living standards and the segmentation of the high-end customized market, the application fields of copper ingots will become more concentrated in the mid-to-high-end range, bringing new development opportunities to the sanitary ware industry.

Impact of New Materials on Sanitary Ware Products: The emergence of new materials, such as stainless steel and zinc alloys, will have a transformative impact on the cost, design, function, and performance of sanitary ware products. The application of these new materials will drive a new round of reshuffling in the market segments of the sanitary ware industry.

05 Quality Requirements for Brass Materials in High-End Sanitary Ware Products

► Special Requirements of the Sanitary Ware Industry for Brass Materials

1. Control of Gas and Non-Metallic Inclusions

During the melting process, various metallic compounds that are insoluble in the matrix metal may be present, whether from raw materials or from tools, furnace linings, or fluxes, leading to the formation of granular, flaky, or blocky inclusions in the material. These inclusions seriously affect the polishing and electroplating performance of sanitary ware products.

Weiqiang's Solution: Adopting ultra-cold crystallisers and grain refinement refining processes to ensure that the metallographic grains of the casting ingots are fine, uniform, and dense.

2. Control of Harmful Impurities

Elements such as S, Sb, and Te are harmful during the melting process. These elements are almost insoluble in copper and form high-melting-point brittle compounds with copper at grain boundaries, increasing the brittleness of the material and affecting its processability. Based on European and American regulations regarding the control of harmful elements to the human body, it is necessary to verify and control these harmful elements during the smelting of raw materials.Weiqiang's Solution: Strict selection, impurity removal, and classification processes are implemented for raw materials. During the smelting process, multiple unique exhaust, slag removal, and refining processes are employed to ensure quality.

3. Casting Liquidity

High-quality copper ingots exhibit excellent casting liquidity, which is particularly crucial for the manufacturing of sanitary products. Good liquidity ensures that copper alloys can flow adequately within the mold, filling every detail of the mold, thereby guaranteeing the shape and dimensional accuracy of the products.

Weiqiang's Solution: In terms of casting liquidity, precise control is exercised over the purification of the melt, refinement of the structure, and control of various elements.

► Significance of Brass in Enhancing the Quality of High-End Sanitary Products

• Improving Product Performance and Reliability

Lead is slightly soluble in copper in a solid state, with the majority existing in copper in a granular form. This enhances machinability and wear resistance. However, during the smelting process, it is necessary to control the lead content, particle size, and distribution to achieve optimal machinability and wear resistance.

Sanitary products have high requirements for the corrosion resistance of copper alloys, such as resistance to dezincification corrosion and stress corrosion cracking. This necessitates control over the metallurgical microstructure and alloying with special elements. Obtaining more equiaxed crystals and adding elements (such as As, Sn, etc.) can enhance corrosion resistance.

• Enhancing the Surface Quality of Brass Sanitary Products

The properties of materials, in turn, affect the service life and applicability of products, especially in humid environments. The design requirements of sanitary products are closely related to the properties of brass materials, influencing the feasibility and innovation of product design. The durability and oxidation resistance of electroplated products directly impact brand reputation and customer perception.

• Green, Environmentally Friendly, and Sustainable Development

The metallurgical quality of copper alloys, particularly the control of harmful element content, is crucial for ensuring the health and safety of sanitary products. Developed countries and regions have imposed strict limits on lead content in drinking water systems to reduce health risks to humans. The metallurgical quality of copper billets also relates to environmental protection issues. After disposal, lead-containing brass can easily release lead into the soil and atmosphere, causing environmental pollution. Therefore, the use of low-lead or lead-free copper alloy materials is of great significance in reducing environmental pollution. The development of environmentally friendly copper alloys reduces the use of harmful substances, making them more friendly to the environment and human health. The use of such materials enhances the safety and market competitiveness of sanitary products. In addition, he introduced the high-end brass products of Guangdong Weiqiang Copper Technology Co., Ltd.