Hot rolled steel sections for elevator guide rails
Hot-rolled steel sections for elevator guide rails are core guiding components in the elevator system. Working in conjunction with the guide shoes on the elevator car, they ensure the smooth ascending and descending of the car and counterweight along a fixed trajectory. Their quality directly impacts the safety, comfort, and service life of the elevator. This type of steel is typically made from low-carbon or low-alloy steels such as Q235 and Q345, and is hot-rolled into specific cross-sectional shapes. Common shapes include T-shaped, L-shaped, and hollow guide rails. T-shaped guide rails are widely used due to their superior guiding stability. Cross-sectional dimensions are designed based on the elevator’s load capacity (500-5000kg) and speed (0.5-10m/s). Heights typically range from 80-200mm, with flange thicknesses of 8-16mm.
The production process for hot-rolled steel sections used in elevator guide rails involves key steps, including billet melting, continuous casting, heating, hot-rolling, straightening, and flaw detection. First, high-quality scrap steel and molten iron are melted in a converter or electric arc furnace. The carbon content is controlled between 0.12% and 0.20%, and the manganese content is between 0.30% and 0.70%. Harmful elements such as sulfur and phosphorus are strictly controlled (≤ 0.035%) to ensure the steel’s weldability and toughness. The continuous casting process utilizes an arc-shaped continuous casting machine to produce rectangular billets. Billet dimensions are determined by the finished cross-section, typically ranging from 150mm × 150mm to 300mm × 300mm. Electromagnetic stirring and dynamic soft reduction techniques are used during continuous casting to minimize center porosity and segregation. The billets are then heated to 1150–1250°C in a walking beam furnace and held there for 2–3 hours to ensure uniform billet temperature and excellent plasticity. Hot rolling is the core process that determines the cross-sectional accuracy of the guide rails. A continuous rolling mill consisting of multiple rolling mills gradually rolls the steel billet to the target cross-section according to the designed pass profile. During the rolling process, the reduction distribution and rolling speed (8-15 m/s) are controlled to ensure flange thickness difference ≤ 0.5 mm and web perpendicularity error ≤ 1°. After rolling, the steel is cooled on a cooling bed to avoid internal stresses. It is then straightened in a multi-roll straightening machine to ensure a straightness error of ≤ 1 mm/m. Finally, ultrasonic testing and visual inspection are performed to eliminate internal defects and surface flaws such as cracks and folds.
The performance advantages of hot-rolled steel for elevator guide rails enable them to meet the stringent requirements of elevator operation. First, sufficient strength and rigidity are the foundation. The tensile strength of Q235 steel guide rails is ≥375MPa, and the yield strength is ≥235MPa, which can withstand the lateral force and impact of the elevator car. The maximum deflection is ≤1/1000 of the span when running at full load, ensuring guiding accuracy. Second, excellent toughness and fatigue resistance, with an impact energy of ≥27J at -20℃, can withstand the repeated loads during elevator start-up and stop, and a fatigue life of 100 More than 10,000 times to avoid brittle fracture; thirdly, high-precision cross-sectional dimensions, flange width tolerance ≤±1mm, web thickness tolerance ≤±0.7mm, ensure uniform fitting clearance (0.5-1mm) with the guide shoe, reducing operating noise; fourthly, excellent welding performance, low-carbon steel composition enables it to be firmly connected by arc welding, gas shielded welding, etc., and the weld strength is ≥85% of the parent material strength, meeting the guide rail splicing requirements; fifthly, excellent surface quality, after hot rolling and shot blasting or grinding treatment, the surface roughness Ra ≤12.5μm, no oxide scale and rust, reducing guide shoe wear.
In application scenarios, hot-rolled steel sections for elevator guide rails are essential components for all types of elevators. In the residential elevator sector, elevators with load capacities of 800-1000kg and speeds of 1.0-1.75m/s often use 100-125mm high T-shaped guide rails, such as the common 8K and 10K models, to balance cost and stability. In the commercial elevator sector, high-load (1600-2500kg) and medium- and high-speed (2.0-4.0m/s) elevators in shopping malls and hotels use 140-160mm high, thickened flange guide rails to improve roll resistance. Medical elevators, which require smooth operation and low noise, use high-precision T-shaped guide rails with elastic guide shoes to ensure vibration acceleration ≤0.15m/s². In the sightseeing elevator sector, some use special-shaped guide rails (such as L-shaped) to balance guidance functions and architectural decorative requirements. In the freight elevator sector, heavy-load elevators (3000-5000kg) use hollow guide rails or double T-shaped combination guide rails to enhance overall load-bearing capacity. With the development of high-rise buildings, ultra-high-speed elevators (6-10m/s) have put forward higher requirements on the straightness and wear resistance of guide rails, which has promoted the application of high-performance hot-rolled steel.
Industry trends indicate that hot-rolled steel sections for elevator guide rails are moving toward high strength, high precision, and lightweight construction. The development and application of high-strength, low-alloy guide rail steel (such as Q460) has increased load-bearing capacity by 30% for the same cross-section, enabling reduced guide rail size and lightweighting. High-precision rolling technology, through online width measurement and closed-loop thickness control, maintains cross-sectional tolerances within ±0.3mm, reducing guide shoe wear. Surface modification technologies (such as hot-dip galvanizing and phosphating) enhance the corrosion resistance of guide rails, making them suitable for use in humid environments (such as underground parking elevators) and extending their service life to over 20 years. Furthermore, the promotion of green production processes, including the use of regenerative heating furnaces and waste heat recovery systems, has reduced specific energy consumption by over 15%. Near-net-shape rolling reduces subsequent processing and increases material utilization to over 90%. In the future, with the increasing intelligence and speed of elevators, the dynamic performance requirements for guide rails will continue to increase, driving the industry to achieve greater breakthroughs in material research and development, process optimization, and performance testing.
