Forum Background: Magnesium Lightweighting Under Dual-Carbon Policy

From July 20 to 21, 2026, the "2026 10th Automotive Fastening and Joining Development Forum," hosted by the Automotive Anti-Corrosion and Aging Branch of the Chinese Society of Automotive Engineering, was held in Qingdao. The forum focused on hot industry topics such as new-energy lightweighting and corrosion-resistant joining of dissimilar materials, bringing together OEMs, three-electric suppliers, and fastener manufacturers to discuss paths for industrial upgrading. The choice of Qingdao is itself significant: Shandong province is a hub for automotive manufacturing and magnesium die-casting research, making it a natural meeting point for the supply chain. The two-day agenda included parallel sessions on corrosion engineering, joining process simulation, and fastener standardization, drawing engineers and procurement leaders from across the country.

The company brought the lightweight fastening solutions from its Xiangyang factory to the event, and Mr. Xu Chaokui, General Manager of Zhichengjia Metal Technology (Xiangyang) Co., Ltd., delivered a keynote speech at the forum. In his opening address, Huang Ping, Secretary-General of the branch, pointed out that against the dual background of the dual-carbon strategy landing and the tightening GB 36980.1 new energy consumption limit policy, vehicle lightweighting has become the key path for new energy vehicles to reduce energy consumption and extend range. Magnesium-alloy materials are being applied at scale to core three-electric components such as battery trays and electric-drive housings. The policy backdrop matters: as regulators push for lower energy consumption per kilometer, every kilogram saved on the vehicle directly translates into extended range or reduced battery pack size, making lightweighting a competitive necessity rather than a nice-to-have.

Keynote: The ZT68 600MPa Joining Solution

General Manager Xu Chaokui presented a talk titled "Lightweight Joining Solutions for New Energy Vehicles - The ZT68 600MPa Cold-Formed High-Strength Aluminum Alloy Bolt." He noted that the current industry-mainstream aluminum bolt strength is only about 420MPa, which is difficult to meet the high-load conditions of three-electric systems and chassis. In contrast, the ZT68 high-strength aluminum bolt produced from the company's proprietary 7xxx modified aluminum alloy reaches a tensile strength of 630MPa, about 50% higher than traditional products, while retaining over 8% elongation toughness.

The presentation walked through the material development, heat treatment process, and surface treatment route that make this strength level achievable in a cold-formed bolt. The audience, composed largely of OEM chassis and battery-pack engineers, showed particular interest in the 60-day anodized salt spray result and the controlled 0.09-0.15 friction coefficient, both of which directly address field pain points they had experienced with imported aluminum fasteners.

Industry Pain Points: Galvanic Corrosion and Preload Decay

The presentation explained the two inherent weaknesses of magnesium-alloy joining thoroughly. The first is galvanic corrosion: magnesium alloy has an electrode potential of about -1.6V, while carbon steel is about -0.44V, a huge potential difference of over 1V. Under humid, water-wading conditions, a galvanic cell readily forms, causing the magnesium substrate to rust and the threads to deteriorate. This is not a slow cosmetic issue; in severe cases, a steel bolt in a magnesium housing can corrode the surrounding material to the point that the housing wall thins or the thread strips within a year or two of outdoor service.

The second is thermal expansion mismatch: the CTE of magnesium alloy is about twice that of steel. Under alternating hot/cold and vibration conditions, the steel bolt and magnesium substrate deform inconsistently, preload continuously decays, and subsequently seal failure, abnormal noise, and loosening occur. ZT68 was developed from the principles of "same-source potential and synchronized deformation" to directly address these two problems. By making the bolt from an aluminum alloy whose electrochemical potential is close to magnesium and whose CTE matches the substrate, both the corrosion-driven and the mechanics-driven failure modes are addressed at the material level rather than being fought with coatings or washings. This "design the material to solve the problem" approach is what OEMs increasingly demand, because it eliminates the failure modes that reappear every time the coating is damaged or the isolation washer is omitted during field service.

Booth Exchanges and Follow-up Engagement

During the forum, the company's booth provided detailed explanations of the ZT68 600MPa high-strength aluminum bolt product. Engineering and procurement teams from numerous OEMs and Tier-1 suppliers visited the booth for exchanges, conducting in-depth discussions on magnesium-alloy fastening corrosion protection and batch customization needs. Many visitors brought specific part drawings and operating conditions, and the technical team was able to give preliminary selection guidance on the spot.

As a company with over twenty years of deep experience in fastener manufacturing, YF Zhichengjia now has a Shenzhen headquarters, a Xiangyang automotive-specialty factory, and overseas bases in India and Indonesia. It obtained IATF 16949 certification in 2013, entered the new energy supply chain in 2017, and pioneered cold-heading mass production of 600MPa-class high-strength aluminum bolts in 2025. Going forward, the company will continue to participate in industry forums in the automotive fastening and joining field, bringing dissimilar-material joining engineering experience to more customers.