In the current era where automotive electrification and lightweighting are deeply integrated, "reducing weight means increasing range, and improving efficiency means reducing costs" has become an industry consensus. Aluminum alloys, with a density approximately one-third that of steel, a mature processing system, and controllable overall costs, are currently the largest-scale and most widely applicable lightweight metal materials for automotive lightweighting. Among them, the 6xxx series (Al-Mg-Si) and 7xxx series (Al-Zn-Mg) two alloy systems, with their balanced forming corrosion resistance and extremely high specific strength, cover almost all core lightweighting scenarios from body outer covering parts, structural profiles to crash safety components.

Against the industry consensus that “weight reduction equals extended range and improved safety” for new energy vehicles (NEVs), lightweighting has long evolved from an optional upgrade to a core proposition in vehicle development.

The first principle in selecting materials for automobiles has never been "pushing for the maximum performance limit", but rather achieving the optimal comprehensive cost across the entire process based on the requirements of the working conditions.

QStE and HC/LA series grades are the most widely used Low Alloy High Strength Steels (LAHS Steel) for current automotive lightweighting.

Driven by the dual trends of automotive electrification and upgraded crash safety standards, vehicle lightweighting and impact protection have become two equally critical core objectives. Featuring ultra-high tensile strength, high-precision forming capacity and remarkable weight reduction effects, press hardening steel (PHS) has turned into the standard material for passenger cabin safety structures of modern automobiles. Its application proportion and strength grade directly define the upper limit of vehicle crash safety and lightweight performance.

Among the technical routes for lightweighting of automobiles and construction machinery, hot-rolled high-strength steel serves as the most widely adopted core structural material with optimal cost performance. It covers a wide range of applications, including frame longitudinal beams and cargo floor panels for commercial vehicles, chassis subframes and control arms for passenger cars, as well as load-bearing structures of battery packs for new energy vehicles. Ranging from 240 MPa high-formability ductile steel to 960 MPa ultra-high-strength steel, the performance limits, process characteristics and failure risks of various grades directly determine the weight reduction ceiling, safety margin and manufacturing cost of structures.

In the triangular competition of lightweighting, high safety and low cost in the automotive industry, advanced high-strength steel has always been the absolute core of the body-in-white material system. From the easily formable outer covering parts to the anti-collision safety structural components, from cold-formed low-carbon steel to 1800MPa grade hot-formed boron steel, the microstructure characteristics, mechanical performance, process windows and applicable scenarios of different steel types vary greatly, directly determining the cost, weight and safety performance of the vehicle body.

High-Strength Interstitial-Free (HS-IF) steel is currently the most widely used advanced high-strength steel grade for automotive bodies, accounting for 30%~40% of the total steel consumption of a vehicle body. It achieves an optimal balance between deep drawability and mechanical strength, making it the primary lightweight material for outer panels and structural components. Data Sources: GB/T 20564.3-2017, Baosteel Standards Q/BQB 413-2009 & Q/BQB 420-2018, Technical Guidelines for Application of Automotive Steel published by China Society of Automotive Engineers (CSAE)

In the vehicle development system, steel sheets serve as the core material for body-in-white and chassis components. From complex-shaped outer body panels and impact-resistant structural reinforcements to load-bearing core parts of chassis and wheels, four major steel categories form the backbone of automotive steel materials: cold-rolled low-carbon steel, low-alloy high-strength steel, and hot-rolled structural steel.

Driven by the dual demands of automotive lightweighting and crash safety, Advanced High-Strength Steel (AHSS) has become the predominant material for vehicle bodies. This article systematically analyzes three widely used core steel grades in the automotive industry: QP steel, a representative of the 3rd-generation AHSS; DH steel, an upgraded version of conventional DP steel; and SAPH hot rolled steel, the mainstream basic grade. All data are sourced from official standards of Baosteel and ArcelorMittal, as well as practical application cases of mass-produced vehicles, serving as reliable references for engineering design and CAE simulation.