Incoloy+825镍基合金法兰锻造工艺分析.pdf

太原理工大学硕士研究生学位论文
Incoloy 825 镍基合金法兰锻造工艺的研究

摘要

本文针对四川普光油气田地面主体开发地面集输工程中所需求的
Incoloy 825 镍基合金法兰毛坯的锻造成形工艺进行了研究。
Incoloy 825 是目前最常用的耐蚀合金之一,其耐蚀性与晶粒的大小密
切相关,细小而均匀的晶粒能极大地提高合金的耐蚀性,然而该合金在锻
造成形中却存在如下的问题:变形抗力大,980 ℃时,其流动应力高达
240MPa;加热和冷却时不发生相变,不能通过热处理方法细化晶粒,只能
通过再结晶来细化晶粒。变形量的均匀程度决定了晶粒大小的均匀性,因
而决定了零件的耐蚀性。为了避免出现粗晶影响整体耐蚀性,还要保证各
处变形量都大于临界变形程度。
虽然该耐蚀法兰是小批量生产,但是由于 Incoloy 825 合金材料价格
昂贵,应该设法提高材料利用率,胎膜锻可以满足这一要求。晶粒的大小
及均匀程度取决于变形过程中的应变场分布,有限元分析是获得该场量的
有效手段。本文用三维造型软件 Pro/E 对不同规格的法兰锻件进行了三维
实体建模,用刚塑性有限元模拟软件 DEFORM 对提出的法兰成形工艺的方案
进行了模拟。模拟结果表明:仅有终锻工步会出现充不满和折迭;而预锻
工步+终锻工步的工艺可避免折迭现象,但仍有末端充不满现象;采用局部
拔长工步+预锻工步+终锻工步的工艺,同时让预锻坯形状与终锻件形状接
近,可确保终锻时坯料以镦粗方式成形,锻件的各处变形量比较均匀且超
过了 25%。试生产也证实了预锻工步+终锻工步和局部拔长工步+预锻工步+
终锻工步的工艺模拟的有效性。最后选定局部拔长工步+预锻工步+终锻工
步的工艺方案实现了整个锻件的顺利成形,完成了耐蚀法兰的锻造生产任
务。
I
太原理工大学硕士研究生学位论文

关键词:Incoloy 825, 耐蚀合金,法兰,锻造,有限元模拟软件 DEFORM

II
太原理工大学硕士研究生学位论文

RESEARCH OF FORGING PROCESS FOR THE FLANGE OF
NI-BASE ALLOY INCOLOY 825



ABSTRACT


The forging process for the Incoloy 825 nickel alloy flange used in the
transport engineering on the ground for the development of Sichuan
Puguang Oil and Gas Field was studied in this paper.
Incoloy 825 is one of the most popular corrosion resistant alloys, and
its corrosion resistance is closely related to the grain size. Small and even
grain can increase the corrosion resistant. However, the primary difficulties
in the forging process of Incoloy 825 are as follows: 825 alloy has large
resistance to deformation, even in the 980 °C ,its flow stress is high up to
240MPa ; 825 alloy had no phase change during heating and cooling, so
the grains can not be refined through heat treatment. The only way to
refine grain is through plastic deformation and recrystallization. The
degree of uniformity of deformation determined the homogeneity of the
grains and the corrosion resistance of the alloy. To avoid appearing coarse
grain which could reduce the corrosion resistance, the de