tailieunhanh - Industrial Machinery Repair Part Episode 2 Part 5

Tham khảo tài liệu 'industrial machinery repair part episode 2 part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 334 Lubrication machine will have lubrication recommendations for maximum temperature range or any oil company will recommend a lubricant to suit. Oiliness Oiliness or the ability to adhere to metal and bearing surfaces is common to all petroleum oils. If a super degree of oiliness is required an additive must be added to the oil. Flash and Fire Points Flash and fire point are considered only when the lubricant is exposed to high temperatures. Flash point is the temperature at which the oil gives off fumes that can be ignited by an open flame usually over 300 F. Fire point is when the oil itself burns and is about 50 F higher than flash point. Flash point depends on a supply of oxygen. Carbon Deposits Carbon deposits are formed when oils are heated to 675 F and higher and occur mainly in the lubrication of steam and internal combustion engine cylinders. Anticorrosives New lubricating oils are noncorrosive to most metals used in machines but through continuous use the oils slowly oxidize and form acids. Some oils contain an additive to prevent acid formation thus extending the life of the oil. On aging in service reactions sometimes take place that result in the formation of insoluble substances. All deposits that settle in lubricating systems are not the fault of oil deterioration but are usually from contamination. At high temperatures the insoluble substances may be deposited as a varnish. Detergent or dispersing agents are added to the oil to keep the deterioration products in a fine state so their separation as a sludge or varnish is prevented. Additives Extreme Pressure EP additives give the oils high film strength to support extreme loads and pressures met with hypoid gears. This oil is not recommended for use on machinery with brass washers bearings or sleeves unless the EP agent is of a type that does not attack brass. Lubrication 335 Antifoaming additives are added to oils used in gearboxes and light oils used to lubricate roller bearings in high-speed .