1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology. Standards NICO-BF PROCESS EDS-M-3304 ISSUED DATE: 2001. 08. 06 REVISED DATE: 2005. 01. 28 VERSION: 3 EDS-M-3304NICO-BF PROCESS PAGE: 1/5 ISSUED DATE: 2001. 08. 06 REVISED DATE: 2005. 01. 28 VERSION: 3 GM DAEWOO Auto & Technolo
2、gy 1. SCOPE This standard shall be applied when some parts (among all parts used by GM DAEWOO Auto & Technology Inc.) go through Oxinitrocarburising process (NICO-BF process), with a view to enhancing surface hardening and corrosion-resistance. 2. METHOD TO MARK HEAT TREATMENT ON THE DRAWING Gas Oxi
3、nitrobarburising process (NICO-BF process) 3. Term 3.1. Oxidation Film: This refers to the Oxidation film of Fe3O4 formed on the outermost surface of the compound in case of NICO-BF process. 3.2. Compound Layer: This refers to the nitrogen layer formed on the surface of a product. It is seen white t
4、hrough the microscope after getting Etching treatment. 3.3. Diffusion Layer: This refers to the nitrogen diffusion layer existing between the surface of a product and the base metal in case of NICO-BF process. Picture 1. NICO-BF Sectioned Drawing (10 30 W )EDS-M-3304NICO-BF PROCESS PAGE: 2/5 ISSUED
5、DATE: 2001. 08. 06 REVISED DATE: 2005. 01. 28 VERSION: 3 GM DAEWOO Auto & Technology 4. QUALITY When it comes to requirements on the hardening layer, standards of Table 1 shall be met. (Note: requirements can be modified according to the agreements between a user and a producer-who shall consider ch
6、aracteristics of each part). Table 1 Standard Code Hardness of a compound layer Depth of a compound layer Depth of a diffusion layer Oxidation Film -Cold Rolled Steel SPCC More than Hv400 More than 10W More than 0.3mm - Carbon Steel: less than 0.3wt%C - Hot Rolled Steel SPHC SAPH SS S10CS28C SUM Mor
7、e than Hv550 More than 10W More than 0.3mm -Carbon Steel: more than 0.3wt%C -Alloy Steel SCM SNCM SK More than S30C More than Hv600 More than 15W More than 0.3mm -Heat Resistance Steel SUH More than Hv800 More than 5WMore than 0.3mm 12W Metal Oxide Layer (Fe3O4) 5. CORROSION RESISTANCE TEST 5.1. NIC
8、O-BF process shall be applied to all parts requiring corrosion resistance. 5.2. Table 2 is the regulations on corrosion resistance. Table 2. Grade Requirements A Grade Red rust shall not exist for 152hours 1)C Grade The regulations of the drawing shall be reflected note 1)In case the rust-preventati
9、ve oil is applied after NICO-BF process. 5.3. Corrosion Resistance Test shall be based on EDS-T-7143 (Salt Spray Test) 6. REQUIREMENTS OF NICO BF 6.1. Pre-treatment EDS-M-3304NICO-BF PROCESS PAGE: 3/5 ISSUED DATE: 2001. 08. 06 REVISED DATE: 2005. 01. 28 VERSION: 3 GM DAEWOO Auto & Technology 6.1.1.
10、Before NICO-BF process, parts surface shall be clean, and neither oxidation film nor decarburizing shall exist. 6.1.2. Parts whose measurements are likely to change because of heat during NICO-BF process can be annealed to remove their stress. Refer to Attachment 1 for more details. 7. RELATED STAND
11、ARD EDS-T-7143 METHOD OF SALT SPRAY TEST EDS-T-7126 METHODS OF MEASURING SOFT-NITRIDING DEPTH 8. REFERENCE STANDARD DES-N-3133(1999. 09. 02) Oxinitrocarburising Process Method (NICO-BF PROCESS) 9. AUTOMOTIVE RESTRICTED HAZARDOUS SUBSTANCES FOR PARTS Material and components must comply with the regul
12、ations stipulated in EDS-A-0101. EDS-M-3304NICO-BF PROCESS PAGE: 4/5 ISSUED DATE: 2001. 08. 06 REVISED DATE: 2005. 01. 28 VERSION: 3 GM DAEWOO Auto & Technology Attachment 1. NICO-BF Process Method In case of NICO-BF process, gas composition and processing time are based on work standards used in a
13、processing place. Its possible to use one of the below A, B, and C processes according to function of each part. However, processing temperature shall be in the below-stated range. As for parts requiring a deep diffusion layer, processing temperature can be modified based on mutual agreements. 580 2
14、0C 1.1. NICO BF PROCESS A Process GAS OXINITROCABURISING + COOLING BUFFING Or POLISHING This is suitable for ROD products requiring polishing (Cr or Ni plate) 1.2. NICO BF PROCESS B Process GAS OXINITROCABURISING + OXIDATION COOLING This is suitable for functional parts for PRESS (Zinc Plating, Alka
15、li Coloring, and Phosphate Film) EDS-M-3304NICO-BF PROCESS PAGE: 5/5 ISSUED DATE: 2001. 08. 06 REVISED DATE: 2005. 01. 28 VERSION: 3 GM DAEWOO Auto & Technology 1.3. NICO BF PROCESS C Process GAS OXINITROCABURISING (2 Stage) + OXIDATION + COOLING This is suitable for parts requiring high function an
16、d corrosion resistance, even though their processing type is similar to NICO-BF B process. 1.4. After NICO-BF process, parts shall be cooled with oil or water. However, you shall take characteristics of each part into consideration. 1.5. Under the agreements with a user, rust-preventative oil can be applied on parts going through NICO-BF process.
