Gray Cast Iron HT250 Used for Castings

HT250 is a widely used gray cast iron material, which occupies an important position in the industrial field with its excellent mechanical properties and good casting processability. As a classic casting material, HT250 plays an important role in many industries such as automobile manufacturing, mechanical engineering, and construction machinery.

From the perspective of chemical composition, the main components of HT250 include C, Si, Mn, P, and S. Among them, the carbon content is usually between 2.9% and 3.5%, and the silicon content is between 1.4% and 2.4%. These elements jointly determine the casting properties and mechanical properties of the material. The higher carbon content makes HT250 have good fluidity and filling properties, which is suitable for manufacturing castings with complex shapes. At the same time, the presence of silicon contributes to the formation of graphite, thereby improving the material's shock absorption and wear resistance.

                                                           equivalent grades of HT250

GB	CNS	JIS	ASTM	SAE	ISO	EN/DIN	W-Nr.
HT25-47	FC250	FC250	250/275	G11H20	250	GG25	0.6025
			35
HT250			35B		JL250
			40
			40B
EN/NF	EN	Number	GOST	SS	BS EN/BS	AS
FGL250	EN-GJL-250	EN-JL1040	SCH25	01-25-00	250	T260
					260
Ft25D				125	Grade220
					Grade260

In terms of mechanical properties, HT250 has a tensile strength of 250 MPa and a hardness range of 170 to 240 HB. This material has excellent wear resistance and shock absorption properties, and is particularly suitable for occasions subject to high loads and vibrations. For example, in the automotive industry, HT250 is often used to manufacture key components such as engine blocks, cylinder heads, and brake discs, which need to work stably for a long time under high temperature and high pressure environments. In addition, HT250 is also widely used in mechanical parts such as machine tool beds, gear boxes, valves and pump housings, and facilities such as pipes, and manhole covers in the construction field.

The advantages of HT250 are not only reflected in its mechanical properties, but also in its economy and processability. As a low-cost material, the raw material and processing costs of HT250 are relatively low, making it suitable for large-scale production. At the same time, its good casting properties enable it to easily manufacture castings with complex shapes and precise dimensions. In addition, HT250 also has good machinability, which is convenient for subsequent machining and surface treatment.

However, HT250 also has some limitations. Due to its poor toughness, the material is prone to brittle fracture when subjected to impact loads, so it is not suitable for high-impact environments. In addition, HT250 has poor welding performance and is prone to cracks during welding, which to a certain extent limits its application in some fields.

In order to improve the performance of HT250, it is usually heat treated. Common treatment methods include annealing and normalizing. Annealing can eliminate residual stress inside the casting and improve the processing performance of the material, while normalizing can increase the strength and hardness of the material, making it more suitable for high-load conditions.