Heatproof castings

Conversion table of produced steels. We prefer to supply final product according to Chomutov marking. On special customer´s request is possible to supply castings according to other standard.

Marking of Chomutov	EU EN	WNr.	DE marked by DIN	FRA AFNOR	UK BSI	ITA UNI
ČSN 42 2912	GX40CrSi17	1.4740	GX40CrSi17	-	-	-
ČSN 42 2913	GX40CrSi24	1.4745	GX40CrSi24	Z 40 C 28 M	452 C 11	GX35Cr28
ČSN 42 2914	GX40CrSi28	1.4776	GX40CrSi28	Z 40 C 28 M	452 C 11	GX35Cr28
AKX30M	-	-	-	-	-	-

ČSN 42 2912 (Cr steel)

Chemical composition in percents

C	Mn	Si	P	S	P+S	Cr	Ni
max.	max.	max.	max.	max.	max.	19.00	max.
0.50	0.90	1.50	0.045	0.040	0.075	22.00	1.00

The castings are delivered as annealed for the stress relieving (+SR).

Mechanical properties and values

Tensile strength	Rm	N/mm2	≥ 392
Hardness	-	HB	200 - 270

*) The values Re, Z, KC and K are not decisive at room temperature because the steel is designed for stresses at high temperatures up to 950°C.Under high temperatures the steel has poor resistance to creep in its intercrystalline borders due to the ferritic basic matrix. The steel is very brittle at room temperature and shall be handled and transported with care!

Resistance to burn-off and chemical agents

• oxidizing + air
  sulfur-free ≤ 950°C
  sulfurous * ≤ 900°C
• reducing
  sulfur-free ≤ 900°C
  sulfurous * ≤ 850°C
  *) concentration of waste products S > 2 g/m³

• Weldability
  This steel is not meant to be welded.
  In exceptional cases, it is possible to weld the steel with much difficulty and under specific conditions: the whole part must be preheated to 700-800°C; after welding allow to cool freely in the furnace; after cooling, it is recommended to repeat annealing.
• Machinability
  Good
• Application
  Furnace parts under lower mechanical stress, e.g. burner nozzles, grate bars, heating plates, pipe and blocks supports, etc.

ČSN 42 2913 (Cr steel)

Chemical composition in percents

C	Mn	Si	P	S	P+S	Cr	Ni
0.40	max.	1.00	max.	max.	max.	24.00	max.
0.70	0.90	2.00	0.045	0.040	0.075	26.50	1.00

The castings are delivered as annealed for the stress relieving (+SR).

Mechanical properties and values

Tensile strength	Rm	N/mm2	≥ 343
Hardness	-	HB	230 - 300

*) The values Re, Z, KC and K are not decisive at room temperature because the steel is designed for stresses at high temperatures up to 1000°C. At high temperatures, the steel has a low resistance to creep at its intercrystalline borders. The steel is coarse-grained, very brittle at room temperature and demands care by manipulation and transportation. The grains can be finer by increasing the content of P.

Resistance to burn-off and chemical agents

• oxidizing + air
  sulfur-free ≤ 1000°C
  sulfurous * ≤ 975°C
• reducing
  sulfur-free ≤ 975°C
  sulfurous * ≤ 950°C
  *) concentration of waste products S > 2 g/m³

• Weldability
  This steel is not meant to be welded. Welding is not recommended.
• Machinability
  Good
• Application
  Annealing vessels for pack hardening, grate bars in combusion chambers, furnace parts (angles and segments), maintenance crucibles for metal baths of aluminum and copper alloys, salt baths in hardening shops, etc. The service life is somewhat shortened when used in temperatures ranging from 400-650°C.

ČSN 42 2914 (Cr steel)

Chemical composition in percents

C	Mn	Si	P	S	P+S	Cr	Ni
0.50	max.	1.00	max.	max.	max.	27.50	max.
0.80	0.90	2.00	0.045	0.040	0.075	30.00	2.00

The castings are delivered as annealed for the stress relieving (+SR).

Mechanical properties and values

Tensile strength	Rm	N/mm2	≥ 294
Hardness	-	HB	250 - 320

*) The values Re, Z, KC and K are not decisive at room temperature because the steel is designed for stresses at high temperatures up to 1100°C.
At high temperatures, the steel has a low resistance to creep at intercrystalline borders of grains and directly in the grains.
The steel is very brittle at room temperature and demands care by manipulation and transportation.
The coarseness can be finer by increasing the content of P.

Resistance to burn-off and chemical agents

• oxidizing + air
  sulfur-free ≤ 1100°C
  sulfurous * ≤ 1060°C
• reducing
  sulfur-free ≤ 1075°C
  sulfurous * ≤ 1020°C
  *) concentration of waste products S > 2 g/m³

• Weldability
  This steel is not meant to be welded. Welding is not recommended.
• Machinability
  Good
• Application
  Annealing pots and retorts, links in recuperators, burner nozzles, parts of furnaces (angles and segments), grate bars, etc. (with a lower limit of Ni content). Corrosion and abrasion resistant runners in pumps (with a higher Ni content). The service life is somewhat shortened when used in temperatures ranging from 400-750°C.

Improvement of heat resistance of this steel can be achieved so that is modified by Molybdenum. It is then delivered under the marking AKX30M and is suitable for grate bars in boiler plant and waste incineration plant.