Maintenance method of the slewing bearing device of the tower (1) The mounting bracket of the slewing bearing of the tower crane (the carrier supporting the lower surface of the ring gear and the seat placed on the upper surface of the inner race) must have sufficient rigidity and the mounting surface To be flat. Before the slewing bearing of the tower crane is assembled, the support shall be subjected to stress relief treatment to reduce the deformation of the slewing bearing. The contact surfaces of the support and the slewing ring must be cleaned during assembly.
Duplex Stainless Steels Available
Yuhong Group supplies LDX2101, 2205, Ferralium 255, Zeron 100 and LDX2507 in the form of plate, sheet, strip, bar, pipe, tubing, pipe fittings, flanges and weld wire.
Duplex Stainless Steel Overview
Duplex Stainless Steels, also referred to as austenitic-ferritic stainless steels, are a family of grades with about equal proportions of ferrite and austenite. These steels have a duplex microstructure which contributes to their high strength and high resistance to stress corrosion cracking. Due to their high content of chromium, nitrogen and molybdenum, duplex steels offer good resistance to local and uniform corrosion. Duplex stainless steels have good weldability.
Today, modern duplex stainless steels can be divided into three groups:
Of the duplex grades, duplex 2205 is the most widely used. However, the super duplex steels like Zeron® 100 and LDX2507 are excellent for servicing severe corrosive environments, such as offshore and marine applications. Lean duplex 2101 is available as an economic alternative to 300 series stainless steels.
(2) Pay attention to the change of noise and the change of the rotary resistance torque during use. If there is abnormality, it should be dismantled.
(3) The slewing bearing of the tower crane must be lifted or stored horizontally. Do not hoist or store it vertically to avoid deformation.
(4) Before the bolt is fully tightened, the gear should be inspected for engagement. The meshing condition should meet the requirements of gear precision: that is, the contact spot distributed on the tooth surface after the gear pair is operated under slight braking is in the direction of the tooth height. Not less than 25%, not less than 30% in the direction of the tooth length.
(5) Tooth surface work 10 shifts should be cleared once and re-applied with grease.
(6) In order to ensure the reliability of bolt operation and avoid the shortage of bolt pre-tightening force, the pre-tightening torque of the bolt should be checked separately after the first 100 hours and 500 hours of the slewing bearing work. The pre-tightening torque should be checked once every 1000 hours of operation.
(7) The bolts and nuts connecting the slewing bearings of the tower crane are made of high-strength bolts and nuts; the double nuts are used for fastening and anti-loose.
(8) When tightening the nut, the lubricant should be applied to the thread of the bolt and the end face of the nut, and it should be tightened symmetrically and evenly in the circumferential direction with a torque wrench. When tightening the last time, the pre-tightening torque on each bolt should be approximately uniform.
(9) Four oil cups are evenly distributed on the upper surface of the ring gear of the tower slewing bearing on the raceway, thereby adding grease to the raceway. Under normal circumstances, the slewing ring is lubricated for 50 hours. Each refueling must be added until the grease is oozing from the seal.
(10) The idling found that the sound was huge. Just like the sound of a mountain bike shift, Kappa Capa. And the hollowing out is serious. It was initially thought that the gold teeth in the tower crane were broken. Or the gear of the card-gold tooth is broken.
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DUPLEX STAINLESS STEEL
Lean Duplex such as LDX2101
Standard Duplex such as 2205, the work-horse grade accounting for more than 80% of duplex usage
Super Duplex such as Ferralium 255 and Zeron 100 and LDX2507
What are the Characteristics of Duplex Stainless Steels ?
Very good resistance to uniform corrosion
Very good resistance to pitting and crevice corrosion
High resistance to stress corrosion cracking and corrosion fatigue
High mechanical strength
Good sulfide stress corrosion resistance
Good abrasion and erosion resistance
Good fatigue resistance high energy absorption
Low thermal expansion
Good weldability
In what Applications are Duplex Stainless Steels® used ?
Oil and gas equipment
Offshore technology
Seawater desalination plants
Chemical industry, especially when handling chlorides
Flue-gas cleaning
Desalination plants and seawater systems
Pulp and paper industry
Cargo tanks and pipe systems in chemical tankers
Firewalls and blast walls on offshore platforms
Bridges
Storage tanks
Pressure vessels, reactor tanks, and heat exchangers
Rotors, impellers and shafts
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