無(wú)縫方矩管的力學(xué)性能是保證無(wú)縫方矩管使用性能（機(jī)械性能）的重要指標(biāo)，它取決于鋼管的化學(xué)成分和熱處理制度。所以根據(jù)不同的使用要求，從抗拉強(qiáng)度、屈服點(diǎn)、伸長(zhǎng)率這幾方面來(lái)具體的介紹下大口徑螺旋鋼管的力學(xué)性能。

The mechanical property of seamless rectangular tube is an important index to ensure the service performance (mechanical property) of seamless rectangular tube, which depends on the chemical composition and heat treatment system of steel tube. Therefore, according to different application requirements, the mechanical properties of large-diameter spiral steel pipe are introduced from the aspects of tensile strength, yield point and elongation.

無(wú)縫方矩管的力學(xué)性能是保證無(wú)縫方矩管使用性能（機(jī)械性能）的重要指標(biāo)，它取決于鋼管的化學(xué)成分和熱處理制度。所以根據(jù)不同的使用要求，從抗拉強(qiáng)度、屈服點(diǎn)、伸長(zhǎng)率這幾方面來(lái)具體的介紹下大口徑螺旋鋼管的力學(xué)性能。

The mechanical property of seamless rectangular tube is an important index to ensure the service performance (mechanical property) of seamless rectangular tube, which depends on the chemical composition and heat treatment system of steel tube. Therefore, according to different application requirements, the mechanical properties of large-diameter spiral steel pipe are introduced from the aspects of tensile strength, yield point and elongation.

1抗拉強(qiáng)度試樣在拉伸過(guò)程中，在拉斷時(shí)所承受的力（Fb），出以試樣原橫截面積（So）所得的應(yīng)力（σ），稱(chēng)為抗拉強(qiáng)度（σb），單位為N/mm2（MPa）。它表示金屬材料在拉力作用下抵抗破壞的能力。

1. The stress (FB) borne by the tensile strength sample during breaking in the tensile process is the stress obtained from the original cross-sectional area (so) of the sample（ σ）， Called tensile strength（ σ b) , in N / mm2 (MPA). It represents the ability of metal materials to resist failure under tension.

2屈服點(diǎn)具有屈服現(xiàn)象的金屬材料，試樣在拉伸過(guò)程中力不增加（保持恒定）仍能繼續(xù)伸長(zhǎng)時(shí)的應(yīng)力，稱(chēng)屈服點(diǎn)。若力發(fā)生下降時(shí)，則應(yīng)區(qū)分上、下屈服點(diǎn)。屈服點(diǎn)的單位為N/mm2（MPa）。

2 yield point the stress of the metal material with yield phenomenon when the specimen can continue to elongate without increasing (keeping constant) the stress during the tensile process, which is called the yield point. If the stress decreases, the upper and lower yield points shall be distinguished. The unit of yield point is n / mm2 (MPA).

3斷后伸長(zhǎng)率在拉伸試驗(yàn)中，試樣拉斷后其標(biāo)距所增加的長(zhǎng)度與原標(biāo)距長(zhǎng)度的百分比，稱(chēng)為伸長(zhǎng)率。以σ表示，單位為%。

3 elongation after fracture in the tensile test, the percentage of the length increased by the gauge length of the sample after breaking to the original gauge length is called elongation. with σ Expressed in%.

今年上半年q345b方管市場(chǎng)價(jià)格將會(huì)出現(xiàn)“慢漲快跌”的一種運(yùn)行狀態(tài)，“慢漲”的原因是由于成本的推動(dòng)，這種成本推動(dòng)體現(xiàn)在鋼廠因原料市場(chǎng)價(jià)格的上漲，生產(chǎn)成本上升，促使鋼廠出廠價(jià)格的上調(diào)；再有，鋼材貿(mào)易商的采購(gòu)成本提高，后期投放市場(chǎng)的采購(gòu)價(jià)格普遍增，但考慮到下游終端用戶(hù)的承受能力，現(xiàn)貨市場(chǎng)上的價(jià)格不會(huì)一下子大幅上漲，而表現(xiàn)為緩慢穩(wěn)步而上。而“快跌”則是受宏觀政策面、鋼材金融屬性以及人為的炒作等原因，一旦鋼價(jià)出現(xiàn)震蕩回落的情況，這些不利因素的疊加效應(yīng)集中顯現(xiàn)，導(dǎo)致市場(chǎng)價(jià)格的快速下跌。

In the first half of this year, Q345B Fangguan's market price will be in a running state of "slow rise and fast fall". The reason for the "slow rise" is due to the promotion of cost, which is reflected in the increase of production cost of steel mills due to the rise of raw material Market price; In addition, the purchase cost of steel traders has increased, and the purchase price put on the market in the later stage has generally increased. However, considering the affordability of downstream end users, the price in the spot market will not rise sharply at once, but will rise slowly and steadily. The "rapid decline" is due to macro policy, steel financial attributes and artificial speculation. Once the steel price fluctuates and falls, the superposition effect of these adverse factors will appear, resulting in the rapid decline of market price.