Hydraulic fittings- raw materials

Classification of carbon steel

(1) according to the use of carbon steel can be divided into carbon structural steel, carbon tool steel and free cutting structural steel, carbon structural steel is divided into engineering construction steel and machine manufacturing structural steel two kinds;

(2) according to smelting method, it can be divided into open hearth steel and converter steel;

(3) According to the deoxidation method can be divided into boiling steel (F), killed steel (Z), semi-killed steel (B) and special killed steel (TZ);

(4) according to carbon content can be divided into low carbon steel (WC 0.25% or less) to carbon steel, medium carbon steel (WC0.25%0.6%) and high carbon steel (WC > 0.6%);

(5)according to the quality of steel, carbon steel can be divided into ordinary carbon steel (containing phosphorus, sulfur is higher), high quality carbon steel (containing phosphorus, sulfur is lower) and high quality steel (containing phosphorus, sulfur is lower) and super high quality steel.

Types of carbon steel

Carbon structural steel

Grade: Example Q235-A·F, σ S =235MPa.

Note :Q is yield strength A quality grade (ABCD 4), F boiling steel.

Features: low price, excellent process performance (such as weldability and cold formability).

Applications: General engineering structures and general machinery parts. Such as Q235 can make bolts, nuts, pins, hooks and less important mechanical parts and building structures in the rebar, steel, steel bar, etc..

High quality carbon structural steel

Grade: Example 45, 65Mn, 08F.

Brand note: direct expression of metal carbon content of ten thousand fractions.

Application: Non-alloy steels used in the manufacture of important mechanical parts, usually after heat treatment.

Common steel numbers and uses:

08F, low carbon mass fraction, good plasticity, low strength, used for stamping parts such as automobile and instrument shell;

20, good plasticity and weldability, used for strength requirements are not high parts and carburizing parts, such as machine cover, welding container, small shaft, nut, washer and carburizing gear;

45,40 Mn, good comprehensive mechanical properties after quenching and tempering, used for mechanical parts with large force, such as gears, connecting rods, machine tool spindles, etc.

60, 65Mn steel has high strength; Used for manufacturing various springs, locomotive rim, low speed wheels.

Carbon tool steel

Grade: for example, T12 steel represents a carbon tool steel with Wc=1.2%.

Note :T plus metal carbon content of the thousand fraction.

Features: Eutectoid steel and eutectoid steel, high strength, hardness, good wear resistance, suitable for manufacturing various low speed cutting tools.

Common steel numbers and uses:

T7, T8: make parts that require toughness to withstand a certain impact. Such as sledgehammers, punches, chisels, carpentry tools, scissors.

T9, T10, T11: tools with low impact and high hardness and wear resistance. Such as tap, small drill, die, hand saw blade.

T12, T13: Make impact-proof tools. Such as file, scraper, razor, measuring tool.

Cast steel

Grade: for example, zg200-400, which indicates the cast steel whose σs is 200MPa and σb is 400 mpa.

Properties: casting properties are worse than cast iron, but mechanical properties are better than cast iron.

Application: it is mainly used to manufacture important mechanical parts with complex shape, high mechanical property requirement, and difficult to be formed by forging and