With the increasing of vertical mills in cement factories, online overlaying were widely used in raw vertical mills.

To reduce the costs of the cement factories, online overlaying is the best choice. It is convenient because it will not dismantle the rollers. This will widely shorten erection time.

① Advantage in online overlaying
a. reduce the overauling cost: saving labor costs for not dismantle the roller and segment. Moreover, people can make repeat overlaying on wear-resistant plate.
b. shorten equipment’s downtime: not dismantle the segment and roller. The overlaying projects can be synchronizing with overhaul time to shorten the downtime.

c. reduce the risk for dismantle the equipment: to avoid cracks that happens in dismantle the roller and segment.

d. flexible time: the construction time for overlaying depends on the arrangement for the user.

e. safety in construction: the online overlaying equipment is compact. No harm to the rollers.

f. suitable for emergency: when there are spalling on wear-resistant parts, online overlaying is able to meet the demands for the overhauling.

g. especially suitable for slag mill: because the slag mill is easy to be worn. If try offline overlaying, there will be several times for dismantle and transportation in one year. Online overlaying can save time.

h. especially suitable for MPS4000B, MLS3626, ATOX50 sectioned roller and segment. It is able reduce the spalling of the edge.

i. especially suitable for round roller with big diameter, for example: POLYSIUS57/28、MPS5600BC、MPS4000B roller. Online overlaying can save lost, labor and time.
j. suitable for segment: there are 8-12 small segments. It is not convenient for dismantling all of them. Online overlaying is more safe and convenient.

k. especially suitable for coal mill with poor quality coal: if the coal is with poor quality, there will be huge assumption for the segment. If try offline overlaying, there will be several times for dismantle and transportation annually. Online overlaying is the first choice.

（a）overlaying for two rollers （b）job site
Online overlaying site for POLYSIUS 57/28 raw vertical mill
（Source: Beijing ARC Xinxing Science & Technology Co.,Ltd. ）