Heat resistant steel grate bar is a critical wearing and high-temperature component for combustion systems. The shell mold casting process, also known as precoated sand shell casting, is the preferred production method for precision heat resistant steel grate bars, including grades 1.4777 and 1.4823. These alloys deliver excellent oxidation resistance, high-temperature strength and thermal fatigue resistance under long-term burning conditions.

The shell mold casting process uses precoated resin sand. A heated metal pattern cures the sand layer to form a hard thin shell mould. Two shell halves are assembled together, and cores are placed to form internal structures. Molten heat resistant steel such as 1.4777 and 1.4823 is poured into the closed shell cavity. Once cooled and solidified, the shell is broken away. The raw grate bar castings go through knockout, cleaning, grinding and comprehensive inspection.

Material Specification: 1.4823 (GX40CrNiSi27-4) – Premium heat-resistant cast steel engineered for continuous high-temperature operation up to 1100°C, offering exceptional oxidation resistance, thermal fatigue resistance, and structural stability in extreme combustion environments.

Baoding Guokun also can customize metal chemical composition to meet your site’s fuel conditions.

Cast iron grate bars: HT200, HT250, RTSi5, ROTSi5, RTCr16, RTCr28, RTCr5, RTCr2Si4Mo, ZG40Cr24, etc. Heating resistant from 550-1200 °C

Heat resistant steel grate bars: DIN 1.4710, DIN 1.4729, DIN 1.4740, DIN 1.4743, DIN 1.4745, DIN 1.4776, DIN 1.4777, DIN 1.4823, DIN 1.4825, DIN 1.4826, DIN 1.4832, DIN 1.4849, DIN 1.4825, DIN 1.4849, DIN 1.4852, DIN 2.4778 heat resistant cast steel moving grate bars

✅ High dimensional accuracy and smooth casting surface, less grinding and machining work

✅ Stable mould hardness, consistent casting quality and low rejection rate

✅ Good repeatability for mass and medium batch production of grate bars

✅ Suitable for high alloy heat resistant steel which is difficult to form by ordinary sand casting

✅ Tight grain structure, helping improve high-temperature wear and thermal shock resistance

✅ Precoated sand shell has good collapsibility, easy shakeout after pouring

⚠️ Material and moulding cost is higher than conventional clay sand casting

⚠️ Not economical for extremely large or ultra-heavy castings

✅ Strict temperature control is required during pouring to avoid alloy segregation and hot cracks

Our shell mold cast heat resistant steel grate bars in 1.4777, 1.4823 and other heat-resistant grades are widely used in municipal waste incinerators, biomass boilers, coal-fired boilers, industrial furnaces, garbage pyrolysis equipment and solid fuel combustion systems. They sustain continuous high temperature, abrasion and alternate hot-cold cycles to keep stable combustion.

Shell Molding Casting: Our Core Advantage

We employ shell mold casting (Croning Process) as our primary manufacturing method, delivering superior quality compared to conventional casting techniques:

The process of Baoding Guokun sand casting involves several steps after producing a professional tool or mold, including:

No.	Steps	Details
1	Pattern Creation	A two-piece metal pattern is created in the shape of the desired part, typically from iron, aluminum or wooden material.For a single casting or small batches of castings, we prefer to produce to use the wooden material to manufacture the mold to save money for customers.For other sand casting parts in large quantity, we prefer to use aluminum or iron to improve the mold’s service life.
2	Mold creation & assembly	The two shell halves are joined together and securely clamped to form the complete shell mold. If any cores are required, they are inserted prior to closing the mold. The shell mold is then placed into a flask and supported by a backing material.
3	Pouring	The mold is securely clamped together while the molten metal is poured from a ladle into the gating system and fills the mold cavity.
4	Cooling	After the mold has been filled, the molten metal is allowed to cool and solidify into the shape of the final castings.
5	Casting removal	After the molten metal has cooled, the mold can be broken and the casting removed. Trimming and cleaning processes are required to remove any excess metal from the feed system and any sand from the mold
6	Machining	CNC machining as per customer’s drawings.

Baoding Guokun Castings specialises in shell mold casting of custom heat resistant steel grate bars. We produce grate bars strictly according to your drawings or samples, with standard grades 1.4777 and 1.4823 available. We provide supporting services including heat treatment, CNC machining, surface finishing, hardness test, chemical composition analysis and NDT inspection. We adopt rigorous quality control for high-temperature alloy castings, support flexible batch sizes and guarantee stable delivery for boiler and incinerator equipment manufacturers.

Contact us and send your technical drawing for a competitive quotation.