The production of microalloyed steels for oil and gas transmission pipelines has increased significantly over the past years.With more and more countries developing their own capabilities to produce pipeline steels to...The production of microalloyed steels for oil and gas transmission pipelines has increased significantly over the past years.With more and more countries developing their own capabilities to produce pipeline steels to support their own internal pipeline infrastructure development,there has been an increase of steel producers working to develop their own capabilities to produce microalloyed steels for this application.However,to achieve the desired mechanical property attributes for transmission pipeline applications utilizing a cost effective approach requires metallurgical optimization of the microalloyed steels.To achieve metallurgical optimization a basic understanding is required in the design of a cost effective alloy and then the proper processing of that alloy design to achieve the optimum microstructure/mechanical properties.In this sense,many producers in the world,especially those who have only recently,in the past 10 years,developed their capability to produce microalloyed transmission pipeline steels still do not achieve metallurgical optimization of their alloy and process.This results in yield losses due to failures,inefficient processing causing productivity losses and additional expensive additions of alloys to compensate for failures and process inefficiencies.Since the supplier of plate/coil has the largest percentage effect on the final cost of the pipe,the steel producer must understand proper alloy,microstructure,and process design to produce a uniform and stable plate/coil to be used in pipe production.This means that strength,toughness and microstructure must be uniform down the length,across the width and through the cross section.Metallurgical optimization is achieved when this uniformity is achieved with a cost effective approach.Counter to that,non-uniformity results in pipe forming,welding,expansion,mechanical property and production issues resulting in downgraded pipe and cost overruns in pipemaking.This paper will describe targets for plate/coil uniformity for pipe production and show examples of pipe issues when uniformity cannot be achieved.Key plate/coil attributes will be identified along with guidelines on alloy design and key processing parameters and targets that need to be considered to work toward metallurgical optimization.Examples will be used to illustrate the thought process in alloy/process design for metallurgical optimization.展开更多
Many new steel plate processing facilities have been built in the past 10 years around the world with many more being planned for the future.This is especially true in developing countries such as China,India and Braz...Many new steel plate processing facilities have been built in the past 10 years around the world with many more being planned for the future.This is especially true in developing countries such as China,India and Brazil.Many of these facilities are plate mills with either one or two stands or a Steckel mill,typically only one stand designed for the production of structural plate steels.Unfortunately,there is a lack of understanding with both the mill builders of the world and the mill owners on the importance of properly matching up the available slab supply (either new as part of a new plate/Steckel mill complex or part of an already existing) with the desired end plate product mix.Many mill builders and owners around the world believe that you can take any slab of any dimension and make any plate dimension you want.While this is basically true with today’s Level 2 automation systems,it does not always result in optimum metallurgy/mechanical properties or productivity.This less than optimum condition results in mechanical property failures,shape issues,productivity losses and in general a less than desirable costly processing operation.It is important to the overall optimization of a steel processing facility that the proper slab dimensions be used to produce the proper final plate dimensions along with achieving the required mechanical properties.The critical nature of this selection will be dependent on the final plate thickness and overall mechanical property requirements.Proper mechanical property,shape and overall microstructure are heavily dependent on the ability to properly work the entire cross section of the slab through the rolling process.Many mechanical property,shape and microstructural issues are a result of improper working of the entire cross section during rolling.The ability for a given mill to properly work the entire cross section is dependent on proper slab selection (total reduction ratio) and a proper rolling schedule either generated manually by the operator or by the mills Level 2 automation system.The proper working and more importantly the true metallurgy of the slab being rolled does not occur until any dimensional rolling passes have been completed.In fact,dimensional rolling passes may create a negative situation that will have to be overcome in the remainder of the rolling schedule.This paper will discuss the importance of proper slab selection for a given plate dimension and final product.Examples and guidelines will be given related to proper slab selection for final plate dimensions and mechanical property requirements.展开更多
文摘The production of microalloyed steels for oil and gas transmission pipelines has increased significantly over the past years.With more and more countries developing their own capabilities to produce pipeline steels to support their own internal pipeline infrastructure development,there has been an increase of steel producers working to develop their own capabilities to produce microalloyed steels for this application.However,to achieve the desired mechanical property attributes for transmission pipeline applications utilizing a cost effective approach requires metallurgical optimization of the microalloyed steels.To achieve metallurgical optimization a basic understanding is required in the design of a cost effective alloy and then the proper processing of that alloy design to achieve the optimum microstructure/mechanical properties.In this sense,many producers in the world,especially those who have only recently,in the past 10 years,developed their capability to produce microalloyed transmission pipeline steels still do not achieve metallurgical optimization of their alloy and process.This results in yield losses due to failures,inefficient processing causing productivity losses and additional expensive additions of alloys to compensate for failures and process inefficiencies.Since the supplier of plate/coil has the largest percentage effect on the final cost of the pipe,the steel producer must understand proper alloy,microstructure,and process design to produce a uniform and stable plate/coil to be used in pipe production.This means that strength,toughness and microstructure must be uniform down the length,across the width and through the cross section.Metallurgical optimization is achieved when this uniformity is achieved with a cost effective approach.Counter to that,non-uniformity results in pipe forming,welding,expansion,mechanical property and production issues resulting in downgraded pipe and cost overruns in pipemaking.This paper will describe targets for plate/coil uniformity for pipe production and show examples of pipe issues when uniformity cannot be achieved.Key plate/coil attributes will be identified along with guidelines on alloy design and key processing parameters and targets that need to be considered to work toward metallurgical optimization.Examples will be used to illustrate the thought process in alloy/process design for metallurgical optimization.
文摘Many new steel plate processing facilities have been built in the past 10 years around the world with many more being planned for the future.This is especially true in developing countries such as China,India and Brazil.Many of these facilities are plate mills with either one or two stands or a Steckel mill,typically only one stand designed for the production of structural plate steels.Unfortunately,there is a lack of understanding with both the mill builders of the world and the mill owners on the importance of properly matching up the available slab supply (either new as part of a new plate/Steckel mill complex or part of an already existing) with the desired end plate product mix.Many mill builders and owners around the world believe that you can take any slab of any dimension and make any plate dimension you want.While this is basically true with today’s Level 2 automation systems,it does not always result in optimum metallurgy/mechanical properties or productivity.This less than optimum condition results in mechanical property failures,shape issues,productivity losses and in general a less than desirable costly processing operation.It is important to the overall optimization of a steel processing facility that the proper slab dimensions be used to produce the proper final plate dimensions along with achieving the required mechanical properties.The critical nature of this selection will be dependent on the final plate thickness and overall mechanical property requirements.Proper mechanical property,shape and overall microstructure are heavily dependent on the ability to properly work the entire cross section of the slab through the rolling process.Many mechanical property,shape and microstructural issues are a result of improper working of the entire cross section during rolling.The ability for a given mill to properly work the entire cross section is dependent on proper slab selection (total reduction ratio) and a proper rolling schedule either generated manually by the operator or by the mills Level 2 automation system.The proper working and more importantly the true metallurgy of the slab being rolled does not occur until any dimensional rolling passes have been completed.In fact,dimensional rolling passes may create a negative situation that will have to be overcome in the remainder of the rolling schedule.This paper will discuss the importance of proper slab selection for a given plate dimension and final product.Examples and guidelines will be given related to proper slab selection for final plate dimensions and mechanical property requirements.
