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Description

FEATURES AND CLASSIFICATIONS

Heat-resistant steel - means one type of steel possesses inoxidizability, enough high-temperature strength and excellent heat-resistant quality under high temperature. Heat resistant steel is divided into oxidation resistant steel and refractory steel according to its performance. Further into Austenitic heat-resistant steel, Martensitic heat-resistant steel, Ferritic heat-resistant steel and Pearlitic heat-resistant steel according to its normalizing.

Pearlitic steel - Alloying elements are mainly chromium and molybdenum.and gross content is no more than 5%, those steels possess excellent high temperature strength, processing property at temperature 500～600℃,low cost. they are widely used to produce the heat resisting parts at temperature below 600℃,such as boiler steel tubings, turbine impeller, rollor, fastener, high pressure vessel, pipeline. and representative steel grades are 16Mo, 15CrMo, 12Cr1MoV, 12Cr2MoWVTiB, 10Cr2Mo1, 25Cr2Mo1V, 20Cr3MoWV.

Martensitic steel - Chromium content is 7～13%, which holds superior high temperature strength, inoxidizability and moisture corrosive resistance,but weldability is not good. 4Cr9Si2, 4Cr10Si2Mo are used to make the vent valves of internal combustion engine, also belong to Martensitic steel

Ferrite steels -  Contains more chromium, aluminum, silicon, forming monophase ferritic structure with superior inoxidizability, high temperature gaseous corrosion resistant capacity.but its high temperature strength is lower, brittleness of room temperature is larger, not well weldability. steel grades like 1Cr13SiAl,1Cr25Si2.

Austenitic steels -  Contains more austenite formative elements like Chromium, manganese, nitrogien. At temperature above 600℃, which possess superior high temerature strength, structure stability, excellent weldability. and representative steel grades are 1Cr18Ni9Ti（321), 1Cr23Ni13（309), 0Cr25Ni20 （310S), 1Cr25Ni20Si2（314), 2Cr20Mn9Ni2Si2N, 4Cr14Ni14W2Mo.
 
MATERIAL SPECIFICATIONS

DIN 17442,17744 (2002/1985), DIN EN 10302, 10095 (2002/1999), EN 10088-1 (2005)
 
CHEMICAL COMPOSITION (WEIGHT %)

C(％):     0.18～0.24
Si(％):    ≤0.50
Mn(％):   0.40~0.90
P(％)≤:   0.025
S(％)≤:   0.015
Cr(％):    11.0～12.5
Ni(％):    0.30～0.80
Mo(％):   0.80～1.20
N(%):       -
Al(%):       -
Nb(%):      -
Other(％):  V0.20~0.35
 
MECHANICAL PROPERTIES (FINAL HEAT TREATMENT OR Q/T) UNDER ROOM TEMPERATURE

Condition: solution treatment
σb/MPa:   700~850
σs≥/MPa:  600
δ5≥(％):   14
Non-scale temperature in Air: 600℃
 
APPLICATION FIELD

Heat-resistant steel is widely used in the field of manufacturing the boiler, steam turbine, motive power machine, industrial furnace, and other mechanical parts of aviation, petrochemical engineering operating at high temperature. Those parts must hold the features: high temperature strength, resistance to high temperature oxide etch, enough toughness, excellent machinability, weldability, structure stability based on different usages.
 
MANUFACTURING TECHNOLOGY - SMELTING

Heat resistant steel is generally smelt in electric arc furnace or induction furnace. For higher quality,it should be smelt via technology of vacuum refining and external refining.
 
HEAT TREATMENT PRACTICE

Pearlitic refractory steels use normalizing or hardening and tempering.

Martensitic heat resistant steels adopt hardening and tempering to stabilize the structure for excellent composite mechanical properties and high temperature strength.
Ferritic steels don't strengthen via heat treatment, which can be annealed treatment at temperature 650～830℃ in order to remove the internal stress due to the plastic deformation and welding.then rapid cooling through the brittleness temperature ranges of 475℃ quickly.

Austenitic oxidation resistant steels generally adopt high temperature solution treatment in order to get a superior cold deformation quality. While austenitic refractory steels firsly adopt hight temperature solution treatment, then ageing treatment to stabilize the structure at operation temperature above 60 ~ 100℃, separate out the second phase to strengthen the matrix.Heat resisting cast steels use in the condition of cast, adopt the relevant heat treatments according to heat resistant steels' categories.
 
PRODUCT PROFILE

Round bar / Wire rod (Diameter):  0.50mm to 800mm
Square bar / Flat bar: 3mm to 800mm
Length: Fixed length or random length or based on the customer's special requirement.
Forging piece: stepped shafts with flanks / discs /tubes /slugs /donuts /cubes /other different shapes based on OEM.