Stainless Steel – Grade 1.4724

//Stainless Steel – Grade 1.4724
Stainless Steel – Grade 1.4724 2018-01-25T09:23:56+00:00

General characteristics

Low-alloyed ferritic heat resisting grade with improved scaling resistance. Uncritical regarding embrittlement at service temperatures. Applied for e.g. furnace equipment, thermal boiler components, grids, burner nozzles, conveying parts, thermowells.

The high temperature (HT) ferritic stainless steels complement Dinesh Tube India’s austenitic heat and creep portfolio. The main alloying element in the ferritic grades is chromium. Its positive effect on the scaling resistance is enhanced by silicon and aluminium. The characteristic properties are excellent resistance to oxidising and reducing sulphur containing atmospheres, good resistance to oxidation and high thermal conductivity with low thermal expansion.

4713 does not form brittle phases but should only be exposed to moderately corrosive atmospheres owing to its low chromium content.

4724 is a truly stainless high temperature grade with 13% chromium. It is not critical in terms of embrittlement. 4742 shows better scaling resistance than 4724 and can be subjected to reducing sulphur environments without risk. It is subject to 475°C embrittlement and grain coarsening at temperatures above 950°C. σ-phase may form after long time exposures to temperatures around 650°C.

4762 – with the highest chromium content- is the most resistant to reducing sulphurous gases. It is susceptible to the same embrittlement phenomena as 4742 whilst σ-phase forms during long exposures in the range 600°C to 800°C.

Characteristic temperatures

The characteristic temperatures for the different grades are shown in the table below.

Steel grade Maximum service temperature in dry air,ºC  Hot forming1,ºC  Annealing2,ºC
4713 800 1100-750 750-800
4724 850 1100-750 800-850
4742 1000 1100-750 800-850
4762 1150 1100-750 800-850

1 Cooling still air        2 Cooling forced air or water

Creep strength

Creep properties of 47XX, Rp0,1 N/mm2 (mean values) are shown in the table below.

Time,h Temperature
500 600 700 800 900
1 000 80 27.5 8.5 3.7 1.8
10 000 50 17.5 4.7 2.1 1.0

Typical applications

Dinesh Tube India Stainless ferritic high temperature steels are mostly used in high temperature applications with sulphurous atmospheres and/or low tensile loads such as for installations within:

  • Furnace equipment
  • Thermal boiler components
  • Grids
  • Burner nozzles
  • Conveying parts
  • Thermowells
  • Chemical industry (drums)
  • Power industry (coal burners)
  • Metalworking industry (heat treatment boxes)

 Composition

  • Al: 0,70-1,20%
  • C: max. 0,12%
  • Cr: 12,0-14,0%
  • Mn: max. 1,00%
  • P: max. 0,040%
  • S: max. 0,015%
  • Si: 0,70-1,40%
  • Balance: max. %

Applications

  • Plant manufacturing
  • Machine engineering
  • Power generation
  • Powerplant

Delivery form

  • Plate, cold rolled
  • Plate, hot rolled
  • Roundbar, rolled
  • welded pipe/ welded tube
  • laser cuts
  • plasma cuts
  • Rings
  • Discs
  • Tailormade drawings