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Material Unibar 350

Unibar 350

Grade Colour Code: Mauve 
Grey/Flake Iron

Comparative Specification:

  • EN-GJL-350 according to BS EN 1561 (2011)

Unibar 350 is a special grade alloyed to achieve specified properties, gives excellent wear resistance and strength. Suitable for all heat-treatment applications, the pearlitic structure giving a better response compared to Unibar 200, 250 and 300, while still possessing reasonable machinability and producing a good surface finish after machining. Noise and vibration damping are good 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
20 < D ≤ 50 315 230 - 300 Pearlitic
  50 < D ≤ 100 280
100 < D ≤ 200 250
200 < D ≤ 400 225
400 < D ≤ 700 225


Contains type ‘A’ graphite flakes in accordance with ISO 945. The rim zone contains fine types ‘D’ and ‘E’ interdendritic graphite. The core matrix is greater than 95% pearlitic. The rim matrix is a ferrite/pearlite mixture. The rim may contain up to 5% dispersed fine carbides.

Heat Treat Response

Unibar 350 is ideal for all conventional methods of heat treatment, with ability to throughharden; hardness levels of up to Rc 50 are achievable.

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


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.


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.


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.


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)

(As-Cast Diameter mm)
Ovality Allowances
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)

(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.


The material grade Unibar 350 is suitable for various applications within the hydraulic and pneumatic industry, the automotive industry, the machinery and machine tool section, for pumps and compressors, within the oil and gas industry as well as for the steel machinery.

Because of its mechanical properties as well as the excellent strength Unibar 350 is often used as a favourable alternative for steel or sand casting.


  • 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 350 is available in your required size, please have a look at our online stock list. Register and keep track of the currently available quantities.