High corrosion protection in the cold rolling process

For high prod­uct qual­i­ty, pro­tec­tion against cor­ro­sion dur­ing coil stor­age & trans­port is the guar­an­tor for the fur­ther pro­cess­ing of cold strips . Effi­cient oil­ing dur­ing cold rolling is ele­men­tary for this in var­i­ous areas of the rolling or slit­ting lines. tech­no­trans devel­oped cus­tomized and sus­tain­able con­cepts for spray oil­ing for sev­er­al pro­duc­tion lines of the BILSTEIN GROUP. This not only enables pro­duc­tion that is gen­tle on resources and health, but also greater flex­i­bil­i­ty and sig­nif­i­cant cost savings.

High prod­uct avail­abil­i­ty requires intel­li­gent stock man­age­ment in steel pro­cess­ing. To ensure the qual­i­ty of the prod­ucts, their pro­tec­tion is a top pri­or­i­ty. In par­tic­u­lar, coun­ter­act­ing cor­ro­sion of mate­ri­als by exter­nal influ­ences even when stored in halls plays an impor­tant role. Even in the cold rolling process­es, man­u­fac­tur­ers there­fore rely on the appli­ca­tion of effec­tive cor­ro­sion pro­tec­tion by means of spe­cial oils. To make them as effi­cient as pos­si­ble, oil­ing equip­ment in cold rolling mills needs to be pre­cise­ly designed for the spe­cif­ic conditions.

New oiling concept for zero-defect principle

Due to the increas­ing demands on prod­uct qual­i­ty and sus­tain­abil­i­ty by its cus­tomers, par­tic­u­lar­ly in the auto­mo­tive indus­try, the Hagen-based com­pa­ny also rec­og­nized a grow­ing need for effec­tive oil­ing of its cold strip to pre­vent cor­ro­sion. This is because in the mile-by-mile man­u­fac­ture of its prod­ucts, the com­pa­ny fol­lows a strict zero-defect prin­ci­ple along the entire process chain in pro­duc­tion. For years, the steel proces­sor had already relied on well-known oil­ing solu­tions from a long-stand­ing sup­pli­er. But the group want­ed to take the process­es to a new level.

Up to now, tech­ni­cal­ly com­par­a­tive­ly sim­ple sys­tems had pro­vid­ed the oil­ing. In its search for a new solu­tion provider, the group came across tech­no­trans’ flu­id exper­tise. Pre­vi­ous­ly active in par­tic­u­lar in the print­ing indus­try and in stamp­ing and form­ing tech­nol­o­gy, the Sassen­berg-based man­u­fac­tur­er trans­ferred its know-how and estab­lished tech­nol­o­gy for air­less spray lubri­ca­tion to the require­ments of cold rolling process­es. Fol­low­ing a suc­cess­ful test phase, tech­no­trans was award­ed the con­tract for equip­ping two plants at the site in the US state of Ken­tucky — and lat­er at oth­er plants in Germany.

Increased cost and process efficiency and flexibility at the same time

“Thanks to tech­no­trans tech­nol­o­gy, we have raised the oil­ing process­es for high-qual­i­ty cor­ro­sion pro­tec­tion of our cold-rolled strip to a new lev­el of qual­i­ty. We save costs, reduce main­te­nance mea­sures on the periph­ery and con­tin­ue to be extreme­ly flex­i­ble in pro­cess­ing oiled and non-oiled cold-rolled strip on just one line.”

- Eugen Schitz, respon­si­ble for plant and process engineering

The tech­no­trans oil­ing sys­tem is used at var­i­ous loca­tions for both re-rolling and slit­ting, as well as on the pack­ag­ing line. For the dif­fer­ent areas of appli­ca­tion, tech­no­trans designed the tai­lor-made solu­tion based on its spray.xact tech­nol­o­gy. The focus was par­tic­u­lar­ly on achiev­ing the high­est pos­si­ble lev­el of effi­cien­cy and sustainability.

The com­pressed air-free spray lubri­ca­tion of the lubri­ca­tion sys­tem turned out to be advan­ta­geous for the require­ments. “In con­trast to con­ven­tion­al solu­tions, the tech­no­trans valves open and close in a pre­de­fined cycle using elec­tri­cal puls­es,” explains Schitz. “Because there are no com­pressed air cur­rents, we achieve uni­form and at the same time low-mist oil­ing” — and this despite the high pro­cess­ing speeds of up to 16 m/s dur­ing cold rolling. The group thus not only achieves a homo­ge­neous result for cor­ro­sion pro­tec­tion, but also saves costs thanks to the high effi­cien­cy of the tech­no­trans solution.

Laterally movable for dry running

The spray bars in the re-rolling lines can be moved lat­er­al­ly elec­tri­cal­ly or pneu­mat­i­cal­ly and are thus not rigid­ly inte­grat­ed in the plant as was pre­vi­ous­ly the case. This results in the fol­low­ing advan­tage for the BILSTEIN GROUP: The steel proces­sor can process the cold-rolled strips both with and with­out spray lubri­ca­tion, depend­ing on cus­tomer require­ments. Because the tech­no­trans com­po­nents are not locat­ed above the con­vey­or belts in the case of unlu­bri­cat­ed prod­ucts, there is no risk of oil droplets get­ting onto the belts dur­ing dry run­ning. “Such impu­ri­ties on our belts would be an absolute dis­ad­van­tage for fur­ther pro­cess­ing — for exam­ple, dur­ing paint­ing,” says Schitz. “Thanks to the tech­no­trans idea, we assure our cus­tomers of high prod­uct quality.”

In the case of re-rolling, the posi­tion­ing of the spray bars on both sides also pro­vides addi­tion­al flex­i­bil­i­ty. The group is able to adapt their process­es accord­ing to the respec­tive require­ments. This is because dif­fer­ent required plate thick­ness­es entail dif­fer­ent rolling inter­vals. “In the end, it does­n’t mat­ter whether the line rolls in an even or odd num­ber,” explains Hary Kosciesza, Busi­ness Devel­op­ment Man­ag­er at technotrans.

“As need­ed, spray noz­zles locat­ed behind or in front of the rolling stand apply the cor­ro­sion inhibitor.” In order for the spray bars to be able to deliv­er the required amount at all dur­ing the high speeds of the cold rolling process­es, tech­no­trans in some cas­es inte­grat­ed dou­ble spray rows with spray noz­zles locat­ed one behind the oth­er per sys­tem. This enables the group to apply oil in quan­ti­ties rang­ing from 0.5 to 2.5 g/m². The fact that machine oper­a­tors can very eas­i­ly set and pre­cise­ly reg­u­late the desired oil quan­ti­ty also makes work easier.

From first order to close partnership

The coop­er­a­tion, which now extends over eight joint projects, start­ed with the estab­lish­ment of a new site in Ken­tucky in the USA. At the new­ly estab­lished BILSTEIN Cold Rolled Steel LP, tech­no­trans devel­oped a spray sys­tem along the slit­ting line, which went into oper­a­tion at the end of 2017. In addi­tion, the oil­ing unit with­in the con­nect­ed pack­ag­ing line sprays the end faces of the coils with cor­ro­sion pro­tec­tion agent.

The group was so con­vinced by the solu­tion for the two process­es that it also made use of tech­no­trans’ exper­tise for oth­er process­es. Already at sev­er­al loca­tions, includ­ing the head­quar­ters in Hagen and the sub­sidiary Hugo Vogel­sang, tech­no­trans spray sys­tems ensure opti­mum oil­ing results in the final pass direct­ly at the rolling mill with­in the re-rolling process in var­i­ous spray widths from 500 mm. Most recent­ly, a new re-rolling, slit­ting line and the asso­ci­at­ed pack­ag­ing line at the main plant in Hagen went into oper­a­tion in Sep­tem­ber with a 1,350 mm wide spray oil­ing system.

BILSTEIN intends to continue relying on technotrans

“Depend­ing on the require­ments of the spe­cif­ic cold rolling line and the needs of BILSTEIN cus­tomers in terms of order vol­umes, we design our solu­tions into the machines,” Kosciesza empha­sizes. For the BILSTEIN GROUP, tech­no­trans devel­oped pre­cise­ly fit­ting spray sys­tems for exist­ing plants or for com­plete­ly new plants in close coor­di­na­tion with the OEM part­ners. The retro­fitting was car­ried out dur­ing the sched­uled down­times of the sys­tems as part of the reg­u­lar main­te­nance intervals.

The com­pa­ny intends to con­tin­ue its mod­ern­iza­tion course in the future not only because of the tech­ni­cal imple­men­ta­tion with tech­no­trans tech­nol­o­gy. The har­mo­nious and tar­get­ed project han­dling from the devel­op­ment of the cus­tom-fit solu­tion through to com­mis­sion­ing also speaks in favor of the Sassen­berg com­pa­ny, says Schitz: “For us, one thing is cer­tain: if we need new solu­tions for cold strip oil­ing, tech­no­trans is our first port of call.”