Swedish lifting fork manufacturer Booforge has found a way to eliminate hydrogen cracks from its gas cutting process. Since introducing Linde´s LINDOFLAMM solution a year ago, it has not seen a single crack.
Booforge Steel makes lifting forks designed to withstand the most challenging conditions. Every one of its products is developed in accordance with customer requirements, and adapted to deliver optimum performance at a certain temperature point.
Problems with hydrogen cracks led to a tailored solution with LINDOFLAMM
As an industry leader in the lifting fork segment, quality and reliability are non negotiable for Booforge. However, until about a year ago, the company had been experiencing a problem in its gas cutting process: “Before gas cutting, the steel has to be pre-heated to between 100 and 200 C,” explains Johan Lundberg, Welding Manager, Quality & Technology, at Booforge Steel. “But, if it doesn’t get sufficiently heated through, hydrogen cracks can occur.”
Johan Lundberg explains that Booforge Steel had previously used handheld propane burners for pre-heating steel. With this process, pre-heating was time-consuming and, in some cases, forks were not getting fully heated through. This, in turn, was causing hydrogen cracks to appear.
Hydrogen cracks often occur after gas cutting, when the hydrogen atoms do not diffuse out but end up in the grain boundaries. The cracks typically appear in the heat-affected zone, and are caused by an interaction between the hydrogen, hard structures – or martensite – and tensions.
Metal working expertise from WELDONOVA® process support
In summer 2018, Booforge Steel received a visit from Linde’s WELDONOVA welding experts, who told them about a solution called LINDOFLAMM. They said it would not only ensure accurate, reliable pre-heating but also significantly reduce the pre-heating time.LINDOFLAMM is a bespoke flame heating solution that enables users to optimise their heating processes, using special burners that are uniquely tailored to fit specific fabrication requirements and matched with the right fuel gas mixture. Apart from being quicker than a standard, off-the-shelf burner, LINDOFLAMM also delivers, more accurate, more reliable and better quality results.
“When we heard the heating time could be reduced from two hours to ten minutes we had to try it,” says Lundberg. “We tested LINDOFLAMM on our materials and immediately reduced the heating time by 75 per cent.”
Although Booforge’s initial reason for investing in LINDOFLAMM was simply to save time, it has resulted in another, even more significant, improvement.
Not one single hydrogen crack since we started with LINDOFLAMM
“Since introducing LINDOFLAMM just over a year ago, we haven’t seen a single hydrogen crack,” comments Lundberg.
“Sometimes you have the perfect solution for a specific problem and, in this case, LINDOFLAMM was spot on, and the success rate has been 100 per cent,” adds Håkan Holmqvist, sales engineer at WELDONOVA.
Last but not least, productivity is also up at Booforge Steel.
“We have quadrupled the number of forks handled per shift. I would encourage any company that pre-heats metal before cutting or welding to take a closer look at this outstanding solution,” Lundberg concludes.
Booforge Steel – a leading player in liftin forks and free-form forging
Headquartered in Karlskoga, Sweden, Booforge Steel’s history dates back to a forging business that began in 1646 and continued for many years within Alfred Nobel’s company Bofors. These days, Booforge Steel operates as an independent business and is a leading player in lifting forks and free-form forging. It employs some 40 people and has an annual turnover of SEK 85 million.
Do you want to know more?
Contact our sales engineer Håkan Holmqvist for more information. Phone: +46 (0)702-43 92 35, e-mail: hakan.holmqvist@linde.com