Mandrel Bars
Mandrel Bars are one of the key pieces of tooling required during the production of Seamless Tubes and Pipes. Once the billet has been pierced, the Mandrel Bar supports the tube shell internally during elongation and wall thickness reduction.
Over the past 15 years API Engineering has supplied over 1,000 mandrel bars to steel mills across the world, built great partnerships and a reputation as a trustworthy, high quality supplier.
Our Mandrel Bar capabilities include, but are not limited to:
- Diameters up to 500mm;
- Lengths up to 25,000mm;
- A variety of seamless tube mill types including;
- MPM, PQF and FQM mills;
- Assel Mills – both floating and retained;
- Plug and Pilger mills;
- Material specification as required, including AISI H13, X35CrMo V51 and 4CrMoSi V1;
- Threading available to API, ACME or metric standards;
- Chrome plating;
- Both solid and hollow bars.
Chemical Composition
For the production of mandrel bars the material is most commonly requested AISI H13, although, this can be changed to meet the customers' requirements.
| AISI H13 (4Cr5MoSiV1) | C | Si | Mn | S | P | Cr | Mo | Ni | V | H | O |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.32 | 0.80 | 0.20 | < | < | 4.75 | 1.10 | < | 0.80 | < | < | |
| 0.45 | 1.20 | 0.50 | 0.008 | 0.012 | 5.50 | 1.75 | 0.25 | 1.20 | 2PPm | 20PPm |
| Size | Tensile Strength (Mpa) | Yield Strength (Mpa) | Elongation (%) | Reduction of Area (%) | Impact Value (J) | Hardness (HRC) |
|---|---|---|---|---|---|---|
| <200mm | 1127-1274 | >931 | >8 | >25 | >20 | 60-62 |
| >200mm | 1078-1274 | >882 | >8 | >25 | >20 | 60-62 |
Manufacturing Process
Our mandrel bars are manufactured using the following processes:
- Steel making (EBT + LF (VD) + ESR);
- Forged using both hydraulic press and rotary forging;
- Annealing;
- Rough machining;
- Magnetic testing;
- Heat treatment – either vertical or horizontal;
- Ultrasonic testing;
- Finish machining including threading if required;
- Chrome plating; and
- Thread phosphating.
Once the mandrel bars have passed inspection they are suitably packaged and shipped directly to the steel mills.
Full documentation is provided with every bar and third part inspection is available if required.