This standard includes two methods: Method A - Increase In Conradson Carbon Residue After Ageing by Passing Air and Method B - Conradson Carbon Residue After Ageing By Passing Air in The Presence Of Iron (III) Oxide
Chapter 1 Method A
1 Subject Content and Application Scope
This standard specifies the method to determine aging performance for lubricating oil.
This standard is applicable to lubricating oil of petroleum base with metallic and non-metallic additive with evaporation loss no greater than 15% (m/m) in the determination process; it is also applicable to the lubricating oil with antioxidant additive and metallic detergent and dispersion agent type.
2 Normative References
GB/T 268 Petroleum Products - Determination of Carbon Residue - Conradson Method
3 Method Overview
At the temperature of 200 ℃, air is passed to the sample twice for aging, in a duration of 6 h every time. Carbon residue of test piece before and after the aging is determined according to GB / T 268 and the aging performance of lubricating oil is indicated in carbon residue value-addition
4 Instrument and Material
4.1 Instrument
4.1.1 Determinator: As in the figure, it is composed of aging tube and its accessories (air introduction tube and exhaust pipe) and all parts are made of borosilicate glass. Air introduction tube is placed in the central position of aging tube and the distance between the tube and the aging tube bottom is 6 mm± 1 mm. The distance shall be marked on the aging tube and accessories to keep the same distance.
4.1.2 Heater: It is a oil bath with stirrer and cover. Bath temperature shall be adjustable and kept at 200℃±0.5℃.At this temperature, the oil in the bath shall be infused to 13 mm from the bath cover and the support of the aging tube shall be fixed so that the aging tube may be immersed in 140 mm from the oil level. Many circular holes are drilled in the oil bath cover and the size is enough for the insertion of oxidation tubes. To avoid the outside air current's effect on the aging tube and the exposed part of the thermometer, the oil bath wall shall be about 150mm higher than the oil bath cover, or a shield in the size as the cover shall be arranged over the oil bath cover.
A metal block heater may also be adopted so that the oil temperature of every aging tube must be kept at 200℃±0.5℃.
4.1.3 Thermometer: It shall be in accordance with those specified requirements in Table 1.
Determinator Figure
1 - Air introduction tube; 2 - Exhaust pipe; 3 - Accessories; 4 - Tapered ground opening;
5 - Aging tube; 6 - 40ml scribed line
Table 1 Thermometer Specification
Thermometer structure type
Measuring range: ℃
Scale value: ℃
Filling material of thermometer
Calibration Mode
Immersion depth, mm
Reference temperature of exposed liquid column: ℃
Top shape
Total length, mm
Mercury bulb length, mm
Distance between the bulb bottom and 195℃graduation line, mm not less than
Graduation length, mm
Outer diameter of capillary, mm
Expanding volume of safety bubble is equivalent to, ℃
Scale mark
Error limit value
Indication error (including the interval error), ℃ Bar shape
195~205
0.1
Mercury and protective gas
Partial Immersion
100
Plus
Circular or spherical
300±10
30±5
165
90±20
6.5±1 5
50
Mark once every 10 small doses
±0.2
4.1.4. Air filter: Glass wool is filled in the wash bottle.
4.1.5 Air flow meter: 40~400mL/min
4.2 Materials
Air: cleaned air.
5 Reagent
Methylene chloride: chemically pure.
6 Preparation
6.1 The aging tube and its accessories are rinsed by the methylene chloride for many times, dried with air, and inject washing liquid of chromic acid at 100℃ and emptied after being kept still for one night. The aging tube and its accessories are rinsed with tap water and then distilled water repeatedly until the distilled water doesn't take on acid reaction and then they are oven-dried.
6.2 The bath temperature is raised to 200℃ ±0.5℃.
7 Test Procedure
At room temperature (18 ~ 28 ℃), the test piece is injected in the aging tube until it comes to the scribed line, accessories are mounted and put in the heater. The air conduit is connected after they have been put at the constant temperature of 200℃±0.5℃ for 20min. The air is introduced into the sample with the flow of 250 ± 4 mL/min and the air gives small bubbles in the aging tube when passing it. The introduction of air stops after 6h. After the aging tube is taken out of the heater and placed at room temperature for 12~18h, the aging process is executed again for 6h under the same conditions. After the aging tube is taken out of the heater and cooled to room temperature, the sample in the aging tube is mixed thoroughly and the carbon residue value is determined in accordance with GB / T 268.
If the sample is placed overnight after being aged, the sample must be put into and heated in the boiling water bath for 20 min. After being mixed thoroughly in the aging tube , the sample shall be cooled until the room temperature and shall be taken out.
Chapter 1 Method A
1 Subject Content and Application Scope
2 Normative References
3 Method Overview
4 Instrument and Material
5 Reagent
6 Preparation
7 Test Procedure
8 Report on Calculation and Result
9 Precision
Chapter 2 Method B
10 Subject Content and Application Scope
11 Normative References
12 Method Overview
13 Instrument and Material
14 Reagent
15 Preparation
16 Test Procedure
17 Calculation
18 Precision
19 Report
Additional Explanation:
