SAPH440 Steel FAQS

What is SAPH440 steel?

SAPH440 steel is one of the most commonly used steel grades in automobile manufacturing. It is a hot-rolled steel for automotive structural use that offers excellent formability, weldability, and dent resistance while being lightweight and cost-effective. Its mechanical properties, toughness and ductility make it an ideal material for a wide range of applications including automotive body panels, suspension components and bumpers. SAPH440 steel is used in a wide variety of industries and has many advantages over other materials, making it a truly reliable choice.

What is the chemical composition of SAPH440 steel?

SAPH440 is a hot-rolled pickled strip steel for automobile structure, which requires high strength, plasticity, cold forming and welding performance, which limits the carbon content in the steel, and the control target is 0.07%~0.1%; Mn is the automobile structure The important elements in the steel are mainly used to refine the grains. Improve the product strength and increase the toughness, and also suppress the hot brittleness of the steel plate caused by S. The control target is 1.2%~1.4%; the S content in the steel is as low as possible to reduce the impact of MnS inclusions and banded structures in the steel on the formability of the steel plate. Harmful effect of Si: Although Si can play a role of solid solution strengthening, it affects the oxide scale structure on the surface of hot-rolled coils and the effect of subsequent pickling. Its content should be reduced as much as possible, and the control target is ≤0.05%. The composition system of hot-rolled pickled steel strip SAPH440 for automobile structure is shown in the following table:

brand Carbon












SAPH440 ≤0.21 ≤0.30 ≤1.50 ≤0.030 ≤0.025 ≥0.010

What are the mechanical properties of SAPH440 steel?

SAPH440 steel is a high tensile strength hot rolled steel. It is used in various automotive applications where strength and durability are required. The properties of SAPH440 steel make it ideal for use in the manufacture of vehicles and parts that must withstand high stress and wear. Following are some key properties of SAPH440 steel:

– Tensile Strength: The high tensile strength of SAPH440 steel makes it ideal for use in the manufacture of vehicles and parts that must withstand high stress.

– Ductility: SAPH440 steel has good ductility, making it suitable for the manufacture of parts that must bend or flex under load.

– Weldability: SAPH440 steel can be welded using standard welding techniques.

– Hardness: SAPH440 steel is relatively hard and wear-resistant.

The specific parameters are as follows:

Yield strength≧305MPa

Tensile strength≧440MPa

Elongation after break≧34%

What is the classification and grade of SAPH440 steel?

  1. Classified according to edge status:

Trimming EC

Uncut edge EM

  1. According to the surface treatment method, it is divided into:

pickling surface

non-acid-washed surface

  1. Classified according to the surface quality grade:

Normal grade surface FA——Features: The surface is allowed to have minor and local defects such as pits, concave surfaces, scratches, etc., whose depth does not exceed half of the steel plate thickness tolerance, but the minimum thickness allowed on the steel plate and steel strip is guaranteed.

Higher surface FB——Features: The surface is allowed to have defects that do not affect the formability, such as slight scratches, slight indentations, slight pitting, slight roll printing, and color difference.

What is the process flow of SAPH440 steel?

Desulfurization → 150 tons of converter vanadium extraction → 150 tons of converter smelting → LF refining → continuous casting → 1780 production line slab heating → high pressure water descaling → rough rolling → hot coil box → finishing rolling → laminar cooling → coiling → inspection-leveling →Packaging→Weight inspection→Reservoir

Steel enters the continuous casting machine

What is the welding method of SAPH440 steel?

SAPH440 steel is an automotive structural steel. It can be welded using any common welding method and produces welds and joints of excellent quality. However, care must be taken to ensure that the steel is ready for welding.

The first step is to clean the steel surface to remove any rust or contamination that might prevent welding. The next step is to set up the welding equipment according to the manufacturer’s instructions. Once everything is ready, you can start welding the SAPH440 steel.

Start by making a series of small spot welds around the perimeter of the joint. Once all the tack welds are in place, you can start welding the body of the joint. It is important to keep welds clean and free of defects; otherwise, they may not be able to withstand the pressure.

When you’re done soldering, let the joint cool completely before continuing. This will help ensure that the joint is strong and does not fail under stress.

worker performing welding operation

What are the applications of SAPH440 steel?

SAPH440 steel is a versatile material that can be used in a variety of applications. Here are some examples of how to use SAPH440 steel:

  • Automotive Body Panels: SAPH440 steel is commonly used in the manufacture of automotive body panels. Steel’s high strength and good formability make it ideal for this application.
  • Electrical appliances: SAPH440 steel has good electrical and thermal conductivity, making it suitable for electrical appliances such as washing machines and dishwashers.
  • Furniture: The excellent strength and stiffness properties of SAPH440 steel make it ideal for use in furniture, especially chairs and tables.

Steel is an integral part of modern industry and its properties are critical to the quality of the finished product. SAPH440 steel is an automotive structural steel widely used in body panels, drive shafts and transmission components.