What Are the Material Requirements for Embedded Parts Used in UHPC Component Installation?

The material selection of embedded parts for UHPC component installation directly affects the safety and durability of the entire curtain wall system, and must meet four core requirements: "strength matching, durability coordination, electrochemical compatibility, and processing suitability". Based on 28 years of engineering experience, Qinglong Group has clearly specified that austenitic stainless steel (grade 304/316) is the first choice for UHPC embedded parts, that 316L stainless steel must be used for critical connection joints, with a characteristic tensile strength value of no less than 500MPa, and that durability matching design with the UHPC substrate is required. In the shaped curtain wall project of the Wuhan Han Show Theatre, all 287 double-curved panels used 316 stainless steel embedded parts and, after years of service, show no signs of corrosion; the roof system of the Hainan International Convention and Exhibition Center, in a marine climate environment, likewise relies on high-quality stainless steel embedded parts to ensure connection reliability. The selection of embedded part materials is the fundamental guarantee of safety in UHPC engineering.

The Absolute Advantages of Stainless Steel

Qinglong mandates that UHPC embedded parts must be made of stainless steel, mainly for the following reasons: first, the coefficient of linear expansion of stainless steel (16-18×10⁻⁶/℃) is relatively close to that of UHPC (10-12×10⁻⁶/℃), reducing thermal stress; second, stainless steel can maintain a stable passive film in the highly alkaline cement-based environment, avoiding electrochemical corrosion. In particular, 316L stainless steel, with the addition of molybdenum, offers significantly better pitting corrosion resistance than 304 stainless steel, making it suitable for coastal areas.

Precise Matching of Material and Strength

The strength grade of embedded parts must match the high-strength characteristics of UHPC. The Qinglong standard stipulates that the yield strength of embedded part steel shall be no less than 300MPa and the tensile strength no less than 500MPa, ensuring that embedded parts do not undergo brittle failure under extreme loads. For the large cantilevered components of the Yirui Biotechnology Building in Shenzhen, we even used 2205 duplex stainless steel with higher strength to meet special load-bearing requirements.

Electrochemical Compatibility Design

Avoiding galvanic corrosion caused by contact between different metals is an important principle in embedded part design. Qinglong requires that all metal components within the embedded part system (bolts, nuts, washers) be made of the same or similar-potential materials. When different metals must be used, isolation measures such as insulating gaskets are adopted, for example, nylon washers installed between aluminum alloy keels and stainless steel embedded parts.

Material Upgrades in Special Environments

For extremely corrosive environments (such as chemical plants and offshore platforms), Qinglong recommends the use of higher-grade stainless steel (such as 254SMO) or titanium alloy embedded parts. Although the cost is higher, this ensures the long-term safety of the project. We have established a complete embedded part material selection guide to provide the most appropriate technical solutions for different projects.