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板形培训资料.ppt

Introduction 介绍
Objective of the Session - What do you want? 研究对象-你要什么?
What is Shape / Flatness? 何谓板形?
What are the different types of off-Flatness? 不良板形的不同类型
Why do we require Flatness? 为什么我们需要控制板形?
How is Flatness measured / quantified?如何测量/确定板形?
What are the various factors that effect Flatness?影响板形的因素
How is Flatness Controlled at the Mills?怎样控制板形
Off-line Flatness / Shape errors离线板形/板形误差
What is Shape / Flatness? 何谓板形?
Shape or Flatness is defines as the strain profile or strain differential across the width of the (平直度)是用整个带宽的应力状况即应力差值来定义。
In simple languages, it is the ability of all portions of the strip, sheet or foil to touch the base when rested on a flat ,板形即是当板带、箔置于平台时其接触平台的能力。
In the process of Rolling, the large forces imposed on the rolls causes them to bend or flatten. Also a lot of heat is generated in the Rolling Process. This and other factors can create a non-parallel roll gap。

This causes uneven reduction across the width of the strip. 此原因使得在带宽上的压下量出现差异。
What is Shape / Flatness? (cont.)(续)
This leads to non-uniform elongation such that the emerging strip is longer in certain portions. For example, the emerging strip may be longer at the middle than at the edges. 这使得在新轧出的带材出现局部变长的不均匀延展。
The middle portion will therefore e wavy to modate the extra length and the strip will not lie flat when relaxed。中部出现波浪而收拉延长部分,当带材离线撤除张力后呈不平状态。
Strip Lengths across the width 沿带宽的长度变化
La
HOW DO THE DEFECTS LOOK LIKE? 缺陷的特征
Full Center Buckle

Edge Pockets 边袋状
Edge Pockets
Edge Wave / Ripple

Edge Ripple
Edge
Ripple
(plant light)
Edge
Ripple
(office light)
WAVY EDGES

CENTRE BUCKLES

QUARTER POCKETS

B’
B
A’
A
B’
B
A’
A
B’
B
A’
A
Lateral Curvature侧弯
Coil-set
Cross-bow弓弯
Definitions: Lateral Curvature侧弯, Cross-bow弓形 and Coil-set卷