高溫下不銹鋼螺栓的材料性能試驗(yàn)研究

張?bào)? 林輝 胡鷹 楊成博

摘 要： 為了給建筑鋼結(jié)構(gòu)螺栓連接的抗火性能分析與抗火設(shè)計(jì)提供依據(jù)，對(duì)不銹鋼螺栓高溫下的力學(xué)性能進(jìn)行試驗(yàn)研究，開展了兩組不同等級(jí)不銹鋼螺栓高溫下的拉伸試驗(yàn)，得到了不同溫度下不銹鋼螺栓的全應(yīng)力 應(yīng)變曲線。對(duì)不銹鋼螺栓高溫下的彈性模量、屈服強(qiáng)度和極限強(qiáng)度進(jìn)行分析，將試驗(yàn)結(jié)果與不銹鋼母材和耐火鋼螺栓在高溫下力學(xué)性能進(jìn)行了對(duì)比，并對(duì)比相關(guān)規(guī)范關(guān)于不銹鋼母材的推薦值，提出了不銹鋼螺栓高溫下彈性模量、屈服強(qiáng)度和極限強(qiáng)度的折減模型。研究結(jié)果表明：不銹鋼螺栓高溫下的極限強(qiáng)度折減系數(shù)與歐洲規(guī)范EC3中對(duì)不銹鋼母材的推薦值相近，彈性模量折減系數(shù)差距較大。溫度低于650 ℃時(shí)，不銹鋼螺栓相比不銹鋼母材屈服強(qiáng)度下降更慢;溫度在500～900 ℃時(shí)，不銹鋼螺栓相比耐火鋼螺栓強(qiáng)度和彈性模量下降更慢。

關(guān)鍵詞： 不銹鋼;螺栓;高溫;彈性模量折減;強(qiáng)度折減

中圖分類號(hào)：TU317.3? ? 文獻(xiàn)標(biāo)志碼：A? ?文章編號(hào)：2096-6717（2020）02-0143-06

Mechanical properties of stainless steel bolts at elevated temperatures

Zhang Jun， Lin Hui， Hu Ying， Yang Chengbo

（School of Civil Engineering， Chongqing University， Chongqing 400045， P.R. China）

Abstract：? To provide the basis for the analysis and design of fire-resistance of bolt connections in steel building， the mechanical properties of the stainless steel bolt at elevated temperature were studied.Two groups of stainless steel bolts with different grades were tested to obtain the full stress-strain curve of stainless steel bolts at different temperatures.The Youngs modulus， 0.2% proof strength and tensile strength of stainless steel bolts were derived.The test results were compared with the mechanical properties of the parent materials and fire-resistant bolts at elevated temperatures， and the recommended values for parent materials in relevant design standards.Based on the experimental data， reduction factors models for tensile strength， Youngs modulus and 0.2% proof strength are proposed in this paper for stainless steel bolts at elevated temperatures.The test results shows that the tensile strength degradation of stainless steel bolts at elevated temperatures are found to be rather close to those recommended by Eurocode 3 for their parent materials， but the reduction factors of Youngs modulus are of great discrepancy.When temperatures lower than 650 ℃， the 0.2% proof strength of stainless steel bolts decreases more slowly than that of their parent materials.In the temperature range of 500 to 900 ℃， the stainless steel bolts retain their tensile strength， Youngs modulus and 0.2% proof strength better than fire-resistant bolts.

Keywords： stainless steel; bolts; elevated temperatures; stiffness degradation; strength degradation

不銹鋼是指以不銹、耐腐蝕性為主要特征，且鉻（Cr）含量至少為10.5%，碳（C）含量最大不超過(guò)1.2%的鋼[1]。不銹鋼構(gòu)件的抗火性能較碳鋼構(gòu)件要好很多，相同條件下的約束柱，不銹鋼的抗火性能能夠達(dá)到碳鋼的兩倍[2]。此外，不銹鋼結(jié)構(gòu)由于其突出的建筑美學(xué)優(yōu)勢(shì)、良好的耐腐蝕性能和較低的全壽命周期成本，迅速在建筑結(jié)構(gòu)領(lǐng)域得到廣泛應(yīng)用，取得了很好的社會(huì)效益和經(jīng)濟(jì)效益，成為最得到認(rèn)可的建筑結(jié)構(gòu)材料[3]。……