NB/SH/T 0517-2014 Evaluation of rust-preventive characteristics of automotive gear lubricants — L-33-1 method

Summary page. This page is a compiled excerpt/summary of the standard — it is not the full standard text and does not replace it. Verify every value against the official standard and the product certificate before use.

NB/SH/T 0517-2014 specifies a test method for determining the rust-preventive characteristics of automotive gear lubricants in a hypoid gear drive axle in the presence of water and under heated conditions, commonly known as the L-33-1 test.

Evidence note: the content of this page was compiled from the original text of this standard held in the Origin Standard library (points marked "[to be verified]" are "[source unclear]" in the original); for individual values and current status, refer to the original pages of the standard and the product certificate.

Scope: This standard specifies a test method for determining the rust-preventive characteristics of automotive gear lubricants in a hypoid gear drive axle in the presence of water and under heated conditions. This test standard is commonly referred to as the L-33-1 test. This standard applies to the determination of the rust-preventive characteristics of automotive gear lubricants. Note: the numerical values in this standard are given in [SI] units; values without a unit designation are in inch-pound units. Not applicable: not provided in the available material.

Principle: This standard uses a drive axle manufactured by DANA, model 30, part No. 27770-1X, ratio 4:10, fitted with uncoated driven and drive gears and a hypoid differential, without drive axle bushings. 4.2 Preparation of the test unit: before each test, completely disassemble and clean a new drive axle assembly, remove the drive axle plugs, and blast-clean all rated parts (excluding bearings and the inner surface of the gear bearing outer races) to remove rust. Before blasting, remove all bearings from the rated parts and apply test oil to the surfaces of all parts inside the drive axle and of the rated parts. Assemble the test unit according to the test requirements, install the unit assembly on the test stand, insert the temperature sensor and connect the drive shaft, and place the fan and heating lamps at the required positions close to the test unit. 4.3 Run-in period: add 1.2 L of test oil to the drive axle and drive the drive axle with an electric motor under no load (no drive axle connecting shaft is used in this test) at a drive pinion speed of 2500 r/min. Then add 30 mL of distilled water to the drive axle (the other holes are all sealed), install the pressure relief system and set the relief pressure to about 7 kPa. When the sample temperature rises to 82.2 °C, close the pressure relief system and the pressure relief system stops working. The drive axle runs continuously at this temperature for 4 h. 4.4 Storage period: after the run-in period, stop the motor. Remove the drive axle from the test stand and place it in the storage box. Hold at a temperature of 52 °C for 162 h. 4.5 Inspection: after the storage period test, the test is complete. Drain the test oil from the drive axle, disassemble the drive axle assembly, and rate rust, stains and other deposits. 5 Application of the method: this test simulates a severe lubricant service condition, in which moisture formed by condensed water vapour that can cause corrosion is present in the drive axle. This may cause the volume of the lubricant in the drive axle to increase or decrease, and moist air is breathed in and out through the drive axle vent. This test can screen lubricants for corrosion-preventive performance.

Apparatus: Laboratory environmental conditions 6.1.1 Test operating room: the test environment should meet the conditions required for an excellent laboratory, free of dust and other contaminants. 6.1.2 Parts cleaning and blasting room: adequate ventilation shall be provided where solvents are used. 6.1.3 Assembly room: it is recommended that the air in the assembly room be filtered and that a constant temperature and low humidity be maintained to prevent dust falling on and rusting of test parts. Otherwise the requirements of 6.1.1 shall be met. 6.1.4 Rating room: all rated parts shall be rated under the conditions required by CRC Manual 21. 6.2 Test stand and test unit 6.2.1 Installation of the test unit: install the differential carrier assembly on the test stand (gear version 99.1 or Vol I) with the rear cover mounting contact face in a vertical position, at a height that allows the temperature sensor to be installed at its bottom. The design dimensions of the test stand are shown in Figures D.1–D.4. 6.2.2 Drive system: no explicit provision is made for the design of the drive system; however, the following equipment has been shown to be suitable for driving the drive pinion at the specified 2500 r/min±50 r/min. 6.2.2.1 Motor, power 1.1 kW, enclosed, speed 3600 r/min, shaft diameter 2.22 cm. 6.2.2.2 Movable motor base (Dyn-Adjust), part No. 20-C. 6.2.2.3 (Dodge) taper-lock pulleys, part No. 40L100 (driven pulley), part No. 28L100 (drive pulley). 6.2.2.4 (Dodge) timing belt, part No. 480L100. 6.2.2.5 Other components such as connecting shafts, couplings and bearing blocks are also necessary for connecting the above test parts and shall be provided by the laboratory. 6.2.3 Steam pressure control system: during the heating stage of the run-in period, the steam pressure in the drive axle is controlled by a water-column pressure relief system connected to the drive axle rear cover, at a controlled pressure of about 6.9 kPa±0.7 kPa. The water-column pressure relief system is connected to the drive axle through a suitably sized NPT stainless steel elbow and a stainless steel full-flow valve. The system also includes an oil reservoir and a return line, which allow the test oil to flow back to the test unit if the test oil foams. The oil reservoir and return line prevent water in the water column from flowing back into the test unit. The system established in Figure D.1 is considered acceptable. 6.2.4 Drive axle rear cover gasket: use a new PTFE gasket for each test in place of the original factory-supplied gasket. 6.2.5 Sealing of the drive axle half-shaft tube openings: since the test differential has no differential half-shafts or rear axle tubes, the drive axle openings must be sealed. Machine a pair of opening seals to the dimensions shown in Figure D.2. The drive axle opening seals shall be installed before the test is started and the test oil is added to the drive axle. 6.2.6 Temperature control system: during the run-in period, the test oil temperature is measured with a resistance temperature detector (RTD) or a thermocouple (type J or K). The temperature controller switches two 250 W lamps and/or a cooling fan. Control the test oil temperature at 82.2 °C±0.6 °C. A household fan with a blade diameter of 31 cm may also be used for cooling. Figure D.3 shows the positions of the heating lamps and cooling fan. Figure D.4 shows the installation position of the thermocouple on the drive axle. 6.2.7 Constant-temperature box and temperature control system: during the storage period, the drive axle assembly is enclosed in a double-walled aluminium box or a stainless steel box. An RTD or thermocouple (type J or K) is connected to the temperature controller to regulate the heat input of four heating tapes, with a total heating power of 500 W. A small motor running at 1550 r/min drives a blade wheel at 1700 r/min±100 r/min to circulate the air inside the box. Control the test oil temperature at 52 °C±0.6 °C. Figure D.5 shows the dimensions of the blade wheel, and Figure D.6 shows the circuit diagram of the insulated box. 6.2.8 Blasting: blast-clean the differential carrier, ring gear, drive pinion, side gears, planet gears, four thrust washers and drive axle rear cover with U.S. No. 80 aluminium oxide coarse abrasive, to remove previously formed rust and obtain a consistent surface. Bearings, the inner surface of bearing outer races and the differential pin shall not be blasted. 6.2.9 This item specifies the blasting equipment and materials. 6.2.9.1 Blasting cabinet: a 36 in.×24 in. blasting machine manufactured by Grainger Econo-Line, model No. 3Z850, or an equivalent product. 1) The blasting machine is used only for blasting L-33-1 test parts. 2) Measure the air pressure at the regulating valve of the blasting gun before it enters the blasting cabinet, and set the regulating valve so that the compressed air pressure entering the blasting cabinet is maintained at 552 kPa±14 kPa. 6.2.9.2 Dust collector: Grainger Econo-Line, collection capacity 28.32 m³/min [1000 f/min], part No. 3JR93, or an equivalent product. 6.2.9.3 Setting of the blasting gun (1) Grainger Econo-Line blasting gun assembly, flow 0.337 m³/min [12 #/min], part No. 3JT01. (2) Grainger Econo-Line blasting gun nozzle internal diameter 1/4 in. (3) Replace part model No. 3JT0813 after 15 blasting operations on L-33-1 test parts. (4) Grainger Econo-Line air jet flow 0.337 m³/min [12 f/min], part No. 3JT04. 6.2.9.4 Blasting material: U.S. No. 80 aluminium oxide coarse abrasive. Replace the blasting material after 15 blasting operations on L-33-1 test parts. Annex D (normative) System diagrams: Figure D.1 pressure control system; Figure D.2 drive axle seals; Figure D.3 arrangement of heating lamps and fan; Figure D.4 thermocouple installation position; Figure D.5 blade wheel; Figure D.6 temperature-controlled storage box; Figure D.7 differential carrier; Figure D.8 drive axle rear cover; Figure D.9 ring gear and drive gear; Figure D.10 drive gear rolling bearing; Figure D.11 differential rolling bearing; Figure D.12 positioning device for drilling threaded holes; Figure D.13 plunger sleeve for drilling threaded holes; Figure D.14 rating template for the drive axle rear cover; Figure D.15 rating block at the contact with the side gear (position 2).

Reagents and reference materials: Special test water: Fisher Scientific deionized ultrafiltered water, catalogue No. W2-4 or W2-20; or water meeting the requirements for grade 3 water in GB/T 6682—2008. 7.2 Solvent naphtha 7.2.1 The solvent naphtha shall meet the requirements of ASTM D235 Type 2 Grade C, with an aromatic content of 0%–2%, a flash point not lower than 61 °C, a Saybolt colour not less than +25 and a platinum-cobalt colour not greater than 25; or it shall meet the requirements for No. 4 solvent naphtha in GB 1922—2006. Warning: solvent naphtha presents combustion and volatilization hazards. 7.3 Rust-preventive oil: Mobil Arma 245 rust-preventive oil or an equivalent rust-preventive oil. Warning: flammable mixture; if swallowed, it may cause injury or death. 7.4 Assembly lubricant: use the test oil to lubricate test parts during assembly. 8 Test oil: 3.7 L of test oil is required per test. The drive axle capacity is 1.2 L; the excess oil is used to coat the test parts during assembly. Blasting material: U.S. No. 80 aluminium oxide coarse abrasive. Replace the blasting material after 15 blasting operations on L-33-1 test parts (see 6.2.9.4).

Key conditions: Drive pinion speed: 2500 r/min±25 r/min (see 11.1.3, 11.1.6, D.2.3.4) Test oil temperature during the run-in period: 82.2 °C±0.6 °C (see 4.3, 6.2.6); clause 11.1.2 gives 83 °C±0.6 °C ([to be verified] ([source unclear]), the temperature values in 4.3 and 11.1.2 of the original are inconsistent) Run-in period duration: 4.0 h±0.1 h (see 11.1.6) Test oil temperature during the storage period: 52 °C±0.6 °C (see 4.4, 6.2.7, 11.2.2) Storage period duration: 162 h±0.2 h (see 11.3.2) Pressure relief system control pressure: about 6.9 kPa±0.7 kPa (see 6.2.3) Blasting compressed air pressure: 552 kPa±14 kPa (see 6.2.9.1) Test oil charge: 1.20 L±0.03 L (see 9.2.2.3); clause 4.3 gives 1.2 L Distilled water addition: 30 mL (see 4.3); clause 11.1.5 gives 29.6 mL±0.6 mL ([to be verified] ([source unclear]), the water additions in 4.3 and 11.1.5 of the original are inconsistent) Drive pinion nut tightening torque: 217 N·m–271 N·m (see 9.2.2.1) Drive pinion starting torque: 0.34 N·m–1.13 N·m (see 9.2.2.1) Bearing cap bolt tightening torque: 48 N·m–68 N·m (see 9.2.2.2) Drive axle rotating torque: 0.8 N·m–1.5 N·m; starting torque: 0.9 N·m–2.0 N·m (see 9.2.2.2) Rear cover bolt tightening torque: 27 N·m–34 N·m (see 9.2.2.4) Temperature sensor installation position: distance from the top to the bottom of the differential carrier 25.4 mm±6.4 mm (see 9.2.1.2) Rinse pressure: shall not exceed 207 kPa (see 9.2.1.4.1) Compressed air/nitrogen blow-dry pressure: shall not exceed 207 kPa (see 9.2.1.4.1) From blasting to rinsing, rinse, blow-drying and application of test oil: to be completed within 2 h (see 9.2.1.7) Interval from blasting to starting the motor: not more than 8 h (see 11.1.4) Time for the test oil to heat to 83 °C±0.6 °C: not more than 1 h (see 11.1.5.1) From the end of the run-in period to placement in the storage box: within 30 min (see 11.2.1) Time for the oil temperature to fall to 52 °C±0.6 °C after the run-in period: not more than 1.5 h (see 11.2.2) Disassembly of the drive axle after the test: within 1 h (see 11.4.1) Cleaning and application of rust-preventive oil after disassembly: within 1 h (see 11.4.4) Rating deadline: within 14 days after the end of the test (see 12.1) Permitted deviation of operating parameters: 5% during the temperature break-in stage, 4% during the test stage (see Table D.1) Limit on number of shutdowns: unlimited during the heating stage; not more than two during the run-in stage, with a total of not more than 15 min; not more than 3 during the storage stage, with a total of not more than 30 min (see D.2.2)

Calculation and results: Rating of results 12.1 Within 14 days after the end of the test, rate the test parts in accordance with CRC Manual 21. Rate the test parts in accordance with CRC Manual 21 and Annex D.4. It is acceptable for the rating procedure described in Annex D.4 to replace the corresponding procedure in CRC Manual 21. Deposits on the rated parts will fall into one of the following two cases: (1) rust or corrosion; (2) stains and sludge or other contamination. 12.2 The rust rating shall be one of the following integers: 10, 9, 8, 5 or 0, using the definitions in Table 1: Table 1 Rust rating | Rust grade | Value | Definition | |---|---|---| | No rust | 10 | Not more than 6 rust spots with a diameter less than 1 mm | | Trace | 9 | 7 or more rust spots, each with a diameter not more than 1 mm, or one or more rust spots with a diameter greater than or equivalent to 1 mm, but the total rusted area not more than 1% of the inspection surface | | Light | 8 | Rusted area not more than 5% of the inspection surface | | Moderate | 5 | Rusted area more than 5% of the inspection surface | | Heavy | 0 | The definition in the "Heavy" row of Table 1 in the original is identical in wording to the definition in the "Moderate" row ([to be verified] ([source unclear])) | 12.3 Rate the inspection surfaces in Table 2 with reference to the definitions described in Table 1. Table 2 Inspection surface number and inspection surface | Inspection surface No. | Description | |---|---| | 1 | Differential thrust face in contact with the planet gears | | 2 | Differential thrust face and bore surface in contact with the side gears | | 3 | Side gear thrust face and outer cylindrical surface in contact with the differential | | 4 | Inner surface of the drive axle rear cover | | 5 | Tooth surface of the driven gear | | 6 | Tooth surface of the drive pinion | | 7 | Roller surface of the drive pinion bearing | | 8 | Inner surface of the drive pinion bearing outer race | | 9 | Roller surface of the differential bearing | | 10 | Inner surface of the differential bearing outer race | 12.4 Record the rating value in the rating form and multiply it by the corresponding weighting factor in Annex D.6 to obtain the final rust merit rating. Record the presence, location and quantity of other deposits, such as stains, sludge or other matter, in the comments column of the rating form. Rust on non-rated surfaces shall also be noted in the comments column of the rating form. 12.5 A rating is considered valid when carried out by experienced personnel who have received professional training. 12.6 Test validity: the test operation is considered valid if the percentage deviations of the required operating parameters and the number of shutdowns are within the limits specified and defined in Annex D.2. 12.7 Severity adjustment: severity adjustment (SA) is calculated for test results obtained with non-reference gear oils. Using the control chart technique with reference to Annex D.5, determine the laboratory bias in rating rust or deposits. Enter the adjusted values in the corresponding test forms. D.2 Calculation and limits of test validity D.2.1 For the test operation to be valid, the number of test shutdowns and the deviations of the required operating parameters shall not exceed the specified limits. D.2.2 Limit on number of shutdowns: D.2.2.1 Heating stage of the test — there is no limit on the number of shutdowns while the test oil is being heated. D.2.2.2 Run-in stage — not more than two shutdowns, and the total time during which shutdowns occur shall not exceed 15 min. D.2.2.2.1 A shutdown is defined as the period during which the test is interrupted until the test operating conditions are re-established. D.2.2.3 Storage stage — not more than 3 shutdowns, and the total time during which shutdowns occur shall not exceed 30 min. D.2.2.4 Do not calculate the percentage deviation when a shutdown occurs. D.2.3 Deviations of test operating parameters: D.2.3.1 The drive axle oil temperature is the parameter that this test method requires to be controlled. D.2.3.2 Calculate the percentage deviation of these parameters using formula (A.1): percent ous = 25 × ) × 0 (A.1) ([to be verified] ([source unclear]), the formula is incomplete in the original) where: M.—the value of the parameter that is outside the range on the i-th occasion; R—the specified range of the test parameter; T.—the time during which the test parameter is outside the range on the i-th occasion, h; D—the test time of the run-in stage or storage stage, h. D.2.3.3 The required percentage deviations of operating parameters are shown in Table D.1: Table D.1 Required limits for operating parameter deviations | Parameter | Break-in stage | Test stage | |---|---|---| | Temperature | 5% | 4% | D.2.3.4 If the average speed of the drive shaft over the whole test stage is outside 2500 r/min±25 r/min, the test is considered invalid. D.6 L-33-1 rust weighting factors are given in Table D.2 Table D.2 L-33-1 rust weighting factors | No. | Differential rating position | Weighting factor | |---|---|---| | 1 | [source unclear] | [source unclear] | Note: only the first row number of Table D.2 is present in the available text; the rating position and weighting factor are [source unclear] ([source unclear]), and the remaining rows are not present in the available text.

Evidence note: [to be verified] and [source unclear] mark specific points that still require checking against the original text of the standard and do not indicate that they have been verified. Do not use these values or steps directly as a basis for work.

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