Blog

Example of New-type Six Valve Grinding

August 07, 2020

From:https://mp.weixin.qq.com/s/iqqqyUkkf1bKk6QWVJk6gw

Types of valve materials

According to the use occasion of the valve, the valve materials can be divided into the following three categories.

1) The applications in automotive gasoline engines are roughly divided into 4 types:

① For light passenger cars and trucks, 40Cr is used for intake valve and 4Cr9Si2、4Cr10Si2Mo steel is used for exhaust valve;

②Medium-sized passenger and truck, 5Cr8Si2、4Cr9Si2 is used for intake valve, 21-4N steel is used for exhaust valve;

③4Cr10Si2 Mo is used for the intake valve of low and mid-range cars, and 21-4N is used for the exhaust valve;

④ 4Cr10Si2Mo、21-4N is used for the intake valve of medium and high-end cars, and 21-4NWNb、Inconel751、Nimonic80A is used for the exhaust valve.

2) For vehicle diesel engines, 4Cr9Si2、4Cr10Si2Mo is used for the intake valve of medium-sized vehicles, XB、MF811、X85CrMoV182、21-12N,23-8N for exhaust valve; 4Cr9Si2、4Cr10Si2Mo、MF811、X85CrMoV182、MF811、X85CrMoV182、 XB, the exhaust valve uses 21-12N, 23-8N, 21-4Nb, ResisTEL.

3) 4Cr9Si2、4Cr10Si2Mo is used in the intake valve of high-speed diesel engines for locomotives and ships; exhaust valves: 4Cr14Ni14W2Mo、21-12N、LF2、LF4 for domestic locomotive diesel engines, 21-4NWNb、ResisTEL、Inconel751、Nimonic80A .

Type

Material grade

Heat treatment state at the time of delivery

Hardness

HB

Tensile strength

Constructional

steel

40Cr

Anneal

≤269

--

45Mn2

Anneal

≤269

--

Martensitic steel

4Cr9Si3

Anneal

≤269

--

5Cr9Si3

Anneal

≤300

--

5Cr8Si2

Anneal

≤300

--

 

4Cr10Si2Mo

Anneal

≤269

--

8Cr20Si2Ni

Anneal

≤300

--

9Cr18Mo2V

Anneal

≤300

--

Austenite steel

4Cr14Ni14W2Mo

Solution

≤255

--

2Cr21Ni12N

Solution

≤209

--

5Cr20Mr8Ni2N

Controlled cooling

≈385

≈1300

1000-1100℃ solution

≤385

≤1300

5Cr21Mr9Ni4N

Controlled cooling

≈385

≈1300

1000-1100℃ solution

≤385

≤1300

5Cr21Mn9Ni4Nb2WN

Controlled cooling

≈385

≈1300

1000-1100℃ solution

≤385

≤1300

6Cr21Mn10MoVNbN

Controlled cooling

≈385

≈1300

1000-1100℃ solution

≤385

≤1300

3Cr23Ni8Mn3N

Controlled cooling

≈360

≈1250

1000-1100℃ solution

≤360

≤1200

High-nickel alloy

GH145

930-1030℃ solution

≤325

≤1100

 

  Common failure modes in valve material processing

The grinding characteristics of valve material in grinding. The abrasive debris is easy to adhere to the surface of the grinding wheel, filling the pores between the abrasive grains, and the grinding wheel loses its grinding ability. This phenomenon is most obvious in high nickel materials, followed by austenitic stainless steel, and martensitic stainless steel is lighter. Because of its high toughness, the grinding debris is not easy to be cut away, and the abrasive grains of the grinding wheel are easy to become dull, which worsens the grinding and causes the grinding wheel to be repaired frequently. The grinding force per unit area is large, up to 68600MPa, the grinding temperature can reach 1000~1500℃, and burns are easy to occur; the surface hardening is serious, which is 1.4~2.2 times the hardness of the substrate, and the hardening depth is 0.1~0.2mm; due to stainless steel The coefficient of linear expansion is 50% larger than that of ordinary steel, causing the workpiece to be easily deformed; austenitic stainless steel is non-magnetic, and it is difficult to grind and clamp.

 

 More Super Hard Valve Case Sharing

 More Super Hard After years of research on valve materials and the accumulation of actual grinding application performance, let's share some actual cases of processing national Emission six emission standard valves.

1. Grinding of valve head: (valve material: high nickel material)

 

Product name

Rough grinding head (external circle + cone) 60° grinding wheel

Specifications

510D-30T-203.2H-60°

Binding agent

Electroplated

Weight

20-25Kg

Dynamic balance

≤0.5g

Installation requirements

Radial runout&end runout  ≤0.003mm

 

 

Workpiece

Margin

φ0.5-1mm

Material

Nickel 30(High-nickel)

Working accuracy

Rz≤10μm

Other requirement

No scratches, burns, vibration marks and other defects on the surface

 Example of New-type Six Valve Grinding

 

 

Machining effect

Processing life

100-120 thousand Pcs

Roughness

Rz≈5μm

Processing time

10s

Stability

Batch processing size is stable, no need to debug

 

2.Grinding of valve lock groove: (valve material: martensite/austenite)

 

 

 

Products name

Locking groove grinding wheel

Specifications

400D*24T*160H

Binding agent

Electroplated

Weight

16-20kg

Dynamic balance

≤0.5g

Installation requirements

Radial runout&end runout  ≤0.003mm

 

 Locking groove grinding wheel

 

Workpiece

Margin

φ1.2mm

Material

Martensitic heat resistant steel

Working accuracy

Ra≤0.8μm

Other requirement

The grinding surface has the same texture, no chatter marks, burns, and no burrs.

 

 More Super Hard Products Co., Ltd

 

Machining effect

Processing life

120-150 thousand Pcs

Roughness

Ra≤0.8μm

Processing time

7~8s

Stability

Batch processing size is stable, no need to debug

 https://www.morediamondwheel.com/products/Grinding_Wheels_for_Auto_Processing_Industry_1.html

 

 
Facebook
 
Twitter
 
LinkedIn
 
youtube
 
pinterest
 
Instagram