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Material Unibar 250

Unibar 250

Grade Colour Code: White 
Grey/Flake Iron

Comparative Specification:

  • EN-GJL-250C according to DIN EN 16482
  • EN-GJL-250 according to BS EN 1561 (2011)

Unibar 250 is a pearlitic-ferritic iron that offers a good combination of strength and wear resistance over Unibar 200, while still possessing good machinability and an excellent surface finish. Due to the graphite structure in Unibar 250 noise and vibration damping along with thermal conductivity are excellent in this grade.

Profile and Size Range

Standard cut length of our cast iron products is 3080mm, other lengths available on request.

Round Square Rectangle Special Profiles
25mm – 700mm 25mm x 25mm – 550mm x 550mm Up to 780mm x 550mm Sizes and profiles to customer design available on request

Mechanical Properties

Material Section mm Tensile Strength
N/mm²
Hardness
(BHN)
Matrix
20 < D ≤ 50 195 160 - 230 Pearlitic - Ferritic
  50 < D ≤ 100 180
100 < D ≤ 200 165
200 < D ≤ 400 155
400 < D ≤ 700 155

Microstructure

Contains type ‘A’ graphite flakes in accordance with ISO 945. The rim contains fine type ‘D‘ and ‘E‘ interdendritic graphite. The matrix is greater than 50% pearlitic. The rim is predominantly ferritic and may contain up to 5% dispersed fine carbides.

Heat Treat Response

Unibar 250 is not recommended for hardening or heat treatment applications.

Ancillary Processes

Both, our foundries and our local distribution centres offer various services to deliver pre-machined products to our customers. Pre-machined Unibar material will save valuable production time, improve the cost effectiveness and eliminate waste in your own production, allowing you to focus on the key design elements of your products.

Cutting

Cutting to specified length in quantities as little as one piece to large volumes, prepared to meet the requirement of your automatic machining systems.

Turning

Turning of round bars to required size to meet specific requirements and to minimise the machining operations of our customers. Unibar turned therefore comes with a standard tolerance of +1mm, although after consultation we can offer alternatives to suit all of our customers‘ requirements.

Milling

Single and duplex machines offer milling of square and rectangular bars to specified dimensions and agreed tolerances. We can offer our customers milling on either four or six faces for further processing.

Peeling

In the case of machined Unibar with diameters of less than 110mm as an alternative to Unibar turned we can offer Unibar peeled by peeling off the oxidised surface layer of the cast bar. As these are smaller dimensions and involve a different machining process, the tolerances offered are more precise, for example h11.

Boring

Longitudinal boring as deep as 1000mm is possible by using single head boring and trepanning machines. Unibar tubes can be supplied with the exterior surface as-cast or machined. These two variants can be complemented by a wide selection of internal measurements, which can range from 30mm to 500mm.

Dimensional Tolerances (Grey/Flake)

Round
(As-Cast Diameter mm)
Ovality Allowances
mm
Max. Swell Allowances mm
20 < (D OR B) ≤ 50 - 5
  50 < (D OR B) ≤ 100 1 7
100 < (D OR B) ≤ 200 2 10
200 < (D OR B) ≤ 300 4 12
300 < (D OR B) ≤ 400 5 15
> 400 By agreement By agreement

Machining Allowances (Grey/Flake)

Section
(D Diameter, B Width)
Min. Machining Allowance mm (per side)
Round Square/Rectangle
20 < (D OR B) ≤ 50 2 2.5
  50 < (D OR B) ≤ 100 3 3.5
100 < (D OR B) ≤ 200 4 4.5
200 < (D OR B) ≤ 300 6 6.5
300 < (D OR B) ≤ 400 7 7.5
400 < (D OR B) ≤ 500 9 9.5
500 < (D OR B) ≤ 650 11 11.5

For rectangular bars the width is the longer dimension of the cross section. Machining allowances of our continuously cast iron bars can be adjusted to meet customer requirements, subject to discussion, prior agreement and special order. For further information please contact our nearest distribution centre.

Applications

Our grey iron Unibar 250 is ideal for an exceptionally wide range of applications. Because of its structure and the mechanical properties it is suitable for the processing within the automotive and glass industries as well as for various applications in the hydraulic and pneumatic section, the machinery and machine tool industry and for pumps and compressors.

In many ways, Unibar 250 has a lot of advantages to compete with other materials such as steel, aluminum or the traditional sand casting.

Advantages:

  • Improved machinability
  • Excellent surface finish
  • 10% weight reduction against steel
  • Excellent vibration damping
  • Faster turning and grinding times
  • Finer grain structure than with sand casting
  • Absence of sand inclusions or cast dimensional problems
  • Elimination of costly patterns
  • Availability from stock

Do you need any further information about our continuously cast iron products? You will find the appropriate data sheets as well as our technical manual in our download section.

To find out whether Unibar 250 is available in your required size, please have a look at our online stock list. Register and keep track of the currently available quantities.