Development of Titanium Process Piping Welding/Assembly
Authors: Gondim Junior J. F. P. , Conzaga C. 
Published: June 2014

The paper presents the step by step from the receipt, storage and transportation, pre-assembly up to the field welding developed in the assembly of titanium process piping. It was possible to verify and list critical recommendations since the handling step until the final evaluation of welding, in addition to the technical characteristics and advantages of using titanium to replace some of the usual materials industry due to its flexibility and mechanical strength, described below and exemplified throughout this work.

The requirements of the manufacturer were the main points to be followed and all the supplier requests were considerable to achieve the higher quality level during the activities. Furthermore, some technics as observe the color of the weld and heat affected zone to check the existence of defects was used during the activities.

Since the use of this material in the petroleum industry is growing up in scale and it has fundamental importance of the chemical and metallurgical point of view, the study has the objective of showing the best practices to erect piping, even knowing the difficulties of weldability. This approach brings several points to growth of knowledge of the activity, mainly due the small bibliography available about this subject.

Introduction

Titanium was recognized as a chemical element more than 200 years ago. Only in the last 40 years, however, it gained strategic importance. During that time, commercial production of titanium and its alloys has grown from zero to well over 23 million quilos per year in the United States. World production of metallic titanium is in the order of 99,000 tons and the main mining areas are in Norway, India, Brazil, Canada, the United States and Russia and their main sources are rutile (TiO2) and ilmenite (TiO3).

The considerable growth was initiated due to the development by Dr. Wilhelm J. Kroll of a relatively safe and economical production of titanium metal in the late '30s. After 1940, the mechanical and physical properties of this element have been defined and the commercial importance of this metal was evident. Currently, the increasing production of titanium is mainly due to the development of biomechanics industry and the expansion of petrochemical industry.

By presenting approximately 60% of the steel weight, excellent mechanical properties such as resistance to corrosion and temperature variations and allows their manufacture in various forms required, the pure metal and its alloys have been used for the manufacture of surgical implants.

In petrochemical industry, the world market is undergoing drastic changes as the growth of production and export capacity of Middle East, the replacement of the United States and Europe to Asia as the main consumer market. Furthermore, the integration of oil refining and petrochemical production is a recurring theme of studies on oil processing, in order to take advantages of synergies in these activities. Thus, as the oxidation reactor of a PTA (Purified Terephthalic Acid) plant and its pipings are lined with titanium, the demand for this element has been continuously increasing.